The moment you unpackage a new smartphone is a magical one. Don't let the moment right after that, when you realize that it's practically useless out of the box, cancel that out. Here's everything you need to know:

What You Need to Buy

There are plenty of smartphone accessories that are worth considering, and a few that you actually need. Proceed with caution, but don't be afraid to treat your new smartphone, and yourself, to a few goodies.

A Case: They look goofy, Jason hates them, and they screw with your device's carefully designed curves. But here's the thing: smartphones are fragile. They aren't like dumbphones, and a single fall—especially with devices with a glass screen—can poop all over your new smartphone party. Until you're trained, play it safe. Wrap your unit. Case brand isn't important, so just take your pick from your local Best Buy or wherever. Just make sure your device's corners are covered, because it's edge impacts that break the most glass. Just remember, you're stuck in a multi-thousand dollar contract with this device, which itself would costs hundreds of dollars to replace. It's actually kind of terrifying! Pretend it's a baby, if that helps.

Headphones: Your smartphone is now your primary media player, too, so you're going to need to ditch the headphones or headset it came with. Yes, they all suck; no, your phone's aren't the one exception. If you don't care about a microphone, treat yourself to a decent pair of in-ear headphones. If you do, get a midrange wired headset.

Storage: Phones either come with internal storage, like the Pre or the iPhone, or taunt you with "expandable" storage, which pretty much means they've got an empty microSD slot. If your phone comes with less than 2GB of space and has said slot, you need to fill it. Buying a microSD card is a little different than buying a regular SD card, because speed doesn't really matter, and nothing you're using your phone demands particularly high transfer speeds. This is a place to store your music, photos and videos—that's it. Buy these online, where branded 8GB cards regularly dip below $20—in stores, you'll pay much, much more. Also, don't worry too much about getting a full-sized SD adapters, as pictured above. Most phones will allow you to mount your smartphone's microSD card as mass storage when they're plugged into a computer, so removal is rarely necessary.

Cables: Pick up a spare charging cable for your phone. For most smartphones this is a simple mini/microUSB cable, while for iPhones it's an iPod dock connector. Why worry about the spare? Think of it this way: if you lose your only iPod cable, you can't listen to music until you buy another one. If you lose your only iPhone cable, you're out of touch with the rest of the world in a matter of hours.

What You Don't

Of course, the temptation of new accessories is great, and there are legions of companies waiting to seize on your post-transactional bliss. When buying smartphone accessories, proceed with caution.

A dock: Again, people have a tendency to confuse their PMPs with their phones, which may look and act similar, but are used in a completely different way. Unless you want to dock your smartphone near your bed to use as an alarm, it's going to be charging—and syncing—with your computer whenever it's not in your pocket. An impulse-purchased dock will, in all likelihood, live a lonely life. Don't let this sad thing happen!

A branded navigation mount: These are almost always overpriced, and all they really do is hold your phone in your line of sight. Just buy a dirt-cheap windshield or dash mount, buy a 12v DC converter to plug your USB charging cable into, and you've got all the functionality you need for about $20.

Cleaning Kits: Cleaning your smartphone isn't hard, and it shouldn't cost you much at all. Just follow our instructions, and avoid any smartphone-specific cleaning kits. They're a guaranteed waste.

Bluetooth anything: Bluetooth headsets can make anyone look like a dweebish soccer dad, and while they might make chatting on the phone while driving more legal, they don't really make it much safer. Just hold your phone like a normal human, put it on speakerphone, or take the call later. You should avoid Bluetooth headphones too, but for a different reason: they suck. They sound terrible, they'll drain your phone's battery and they're overpriced. If you have to buy a pair, spend as little as possible.

Getting Started

If your smartphone is a newborn, this is where we teach it to walk.

Contacts: Somehow, in over two decades of cellphone development, we haven't settled on a simple way to transfer contacts from one phone to another. Here's how you should proceed through this somehow-still-painful process:
• Get your carrier to do it. If you're upgrading handsets on one carrier, they should be able to transfer your contacts, and probably for free. If you're switching carriers, there may be a small fee. Don't spend more than five bucks.
• Use your SIM. Are you on AT&T or T-Mobile? Is your smartphone on the same carrier as your old dumbphone? Most phones will have an option to write all contacts to a SIM card, which is the little chip that your phone uses to identify itself on a cell network. Do this, pop your old card out, pop it into your new smartphone, and transfer all your contacts from the old SIM onto your new phone's memory. Sadly, this won't work with Verizon or Sprint phones, which are CDMA-based, and therefore don't have SIM cards at all.
• Google Sync. Through a protocol called SyncML, Google Sync supports quite a few features phones, and can pull all your contacts into your Google account. Your new smartphone can then yank them back down from the cloud. Bonus: they're now backed up to Google server's, too.

Email: Email, you'll find, is one of the best things about owning a smartphone. Setting up your email varies from smartphone to smartphone (iPhone, Android, Palm Pre, Windows Mobile) and service to service (Exchange and Gmail setups will be completely different, obvious) but there are few rules of thumb to keep in mind during account setup. For example, use IMAP (versus POP) whenever you can—this will keep your messages and their read/unread statuses in sync with your desktop clients. And since most of your email downloading will be happening over 3G, set the individual message size limit at or below about 10kb. This will ensure your messages come in quickly, but also that you have something to read once they arrive.

Calendars: If you keep a Google Calendar, having it sync with your smartphone is a revelation. Android phones will automatically sync with your default Google account's calendars, as will the Pre, while the iPhone will need to be configured with CalDav. If you don't keep a calendar, your new smartphone is a good excuse to start.

Media and Syncing: Most smartphones rely on some kind of desktop software to transfer personal info, music, video and photos to and from the handset. For the iPhone, this basically means downloading iTunes—which you have to do anyway. For BlackBerry, this means downloading BlackBerry Desktop Manager. Windows Mobile phones are best served by Windows Device Center, while Android and Palm phones—and optionally Windows Phones, iPhones and BlackBerrys—play nice with doubleTwist, a cross-platform music player/media syncing app.

Converting Video: You can't just copy your torrented videos or home movies over to your smartphone; you need to downsample those videos, stat. Just download Handbrake for this—it's basically magic, and it works on Windows, OS X and Linux. These instructions are iPhone-centric, but videos converted to 320x240 h.264 will be suitable for most new smartphones.

Apps! Apps! Apps! Apps!

Without apps, smartphones are nothing. With apps, they're practically anything. Every smartphone platform has an app storefront now, from Apple's pioneering App Store to BlackBerry's App World to the Android Market, and they're all, to different extents, treasure troves.

iPhone: First stop, Gizmodo's Essential iPhone Apps Directory. These are the best of the best, and everything you need to make your iPhone into a mobile powerhouse. If you're averse to spending money on your new iPhone—this thing wasn't cheap, after all—check out our Essential Free Apps. We do regular posts and weekly roundups around here too, so just keep an eye out.

Android: It's got the second best app selection, which is to say there's some really great stuff out there. Our Essential Android Apps roundup cuts through the noise of the App Market, while our monthly roundups keep you up to date with the latest additions to the store.

BlackBerry: We cover the biggest new additions to App World, but it's best to defer to a specialist site like CrackBerry for this one—they have their own app store too, which isn't really much better or worse than BlackBerry's janky official shop.

Palm: We've just pulled one of our patented "Essential" roundups fresh out of the oven, so consult that first. Beyond that, PreCentral's official app reviews are fairly fantastic. Also worth checking out is their extensive homebrew app gallery, which has about as many decent apps in it as the official Catalog.

Windows Mobile: App development for WinMo isn't exactly picking up nowadays but there's a tremendous backlog of useful reviews and materials at WMPowerUser, WMExperts, XDA and MoDaCo. And yeah, we occasionally still do Windows Mobile app roundups, though until things get exciting again, expect less, not more.

Living Happily Ever After

Lastly, a few odds and ends to make sure your metal'n'plastic darling lives a happy life, at least before the end of its two-year contract.

How to back up your smartphone: Your smartphone probably contains as much personal data as your computer, and it's subjected to way more physical risk. Preempt the pain. Back it up.

How to keep you smartphone clean: These little machines are fantastic at collecting fingerprints, dust and grime. Wipe them off every once in a while.

Any other tips for new smartphone owners? Chuck them down in the comments. Happy Holidays!