Determine the intended use of the tent before you make your purchase. For fair-weather camping, a well-strung tarp can serve as a shelter, and tarps are lighter and cheaper than tents.

Get a tent that doesn't require many stakes. Stakes are heavy, easy to lose and make it difficult to pitch the tent on hard or soft ground or on snow.

Look for a tent with a fly that closes completely and has a vestibule for storing packs and boots out of the rain.

Stick with the three-season variety of tent, which can handle moderate winter use, unless you plan extreme mountaineering or expedition use. Four-season tents, designed to handle extreme weather, are much heavier than their three-season cousins.

Find a big stuff sack for the tent so that you don't have to go to extreme lengths to cram it into the bag and potentially cause damage to the tent.

Buy the lightest tent that meets your needs and budget.

Tips:

Don't be oversold by sales representatives when you are shopping. What you need is what you need - nothing more, nothing less.

Make sure you know how to set up your new tent before you take it into the wilderness. Practice in your backyard.

Warnings:

Remember not to store food in your tent so animals won't chew their way in.

Tips from eHow Users:

Buying a Tent by Loren H.
Purchase a tent with "sealed or taped seams" to prevent moisture leaking into your shelter. Most tents come with taped seams now, but make sure! Also, it's a good idea to add some liquid seam sealer yourself for more protection. (It's usually only about $5.00 a bottle and dries quickly.)

Tent bottom
Make sure that the tent bottom has as few seams as possible and that the seams are off the ground and covered. Otherwise, you can end up with water inside the tent if it rains.


 
Information gathered from Ehow.com - The Ultimate 'How To' Manual
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