If you're having trouble with, or want to enhance your PS Vita, I'm slowly putting together some tips and troubleshooting guides.
The most common tip is for a locked, crashed Vita or one with a constantly flashing blue PS light. Simply hold down the power button for a few seconds (sometimes with the right trigger pressed) - until you see the restart menu. Choose the first "Restart the PS Vita System" option and that should do the trick.
Memory Card Content Vanishing?
PS Vita Error Code c1-11834-7
Missing PS Vita AR cards
Cleaning out your memory card
Choose your Vita's lock screen
If you're after some cool backgrounds and lock screens for your Vita then these are a few good places to visit. Remember you can take screenshots of your own games in action (Press PS Button and Start) and use those!:
Reddit forum thread
Free Vita themes
If you're looking for something extra to protect, enhance, or otherwise cuddle your Vita, check out these links.
Turtle Beach M5 Headphones
Sony Pulse Wireless Elite Edition Headset
PS Vita Case Roundup
Sony PS Vita Cases and Accessories
Nyko PS Vita Dock
Snakebite PS Vita Cases and Accessories
DX Combined grip and battery pack
Games like Borderlands 2 mean you could need a grip more than ever, I haven't tried one, but these seem popular on Amazon: