Don't think that just because a tent is expensive it's the best choice.  Different tents are made for varying activities, and you need to decide how yours will be used.  There are the big and bulky family tents that don't pack very small.  There are lightweight solo models designed for serious backpackers needing all the room they can get in their pack, without much weight.  And there are numerous styles of tents that fill the gap between these two extremes.

First, figure out where most of your escapades are going to take you.  Most tents have a weather rating. If you're going to be staked out in a warm climate, you won't need to pay extra for a model rated for exreme cold weather.  Another consideration is, will you need a free-standing domicile?  For the serious mountain explorer, this is the best bet. Mountains often don't offer places to shove stakes and set poles. But for the family camper who enjoys the maintained campgrounds in most state parks, a regular tent will do just fine.

Set-up time and durability are important factors as well. High-priced tents usually come with thin poles and light materials, but if you'll be driving to your campsite, don't clean out your wallet to get the lightest shelter available.

Purchase a tent according to the terrain it will be used on.

Make sure you choose a tent with durable fabric.  It may cost a little more, but this is definitely an area where you want to spend extra money. 

There are many different groundsheet materials to choose from.

• Neoprene-coated nylon -- Stronger, yet heavier than the average groundsheet, usually for mountain camping to keep rocks from poking through.   
• PVC coated nylon -- This is the heaviest.  Used for larger family tents.    
• Polyurethane-coated nylon -- The norm for lightweight tents.  Good for backpackers who don't want to carry a lot of weight.    
• Polyethylene -- Strong but heavy and usually used on lesser-priced models.

Picking a tent with a good rainfly can also make the difference between a good night's sleep and a soggy one.  Here are some of the different materials available:

• Canvas -- Heavy material that doesn't readily collect water, but but is prone to mildew.   
• Polyurethane-coated nylon -- A very lightweight material with a small pack size.  But unless it is treated with UV inhibitors, the sun with eventually break down the PU treatment and material and make it more susceptible to tearing.  This material also tends to bring in condensation.    
• Polyurethane-coated polyester -- A very water-resistant material and doesn't sag much when wet, but the PU treatment is even more susceptible to UV rays than nylon and also brings in condensation.    
• Silicon-elastomer-coated nylon -- One of the best water-repelling rainfly materials available.  The coating actually strengthens the tearability of the tent.  With coating on both sides of the material, the fly won't sag under wet conditions.

Your destination should determine the packablilty of the tent.

The shell of the tent is more of a matter of options and features.  As long as you're protected from air and land with a good groundsheet and a rainfly, a shell with a light silicone coating will keep you dry and happy.  The question is whether you want to pick a tent with a lot of windows to see the sky, or choose one that keeps out the cold at all costs.  

Features to look for in a tent:

• Double-skin walls, for cold weather tents.    
• Flashlight hooks and pouches for lighting and gear.    
• UV-resistant windows.    
• Ventilation chimney -- keeps condensation and water out of tent for cold-weather camping.