There are many tents out there today. Knowing the difference in form, function, and sizing is important to making the right tent choice.

Form - Single or Double Wall, Freestanding vs Staked Design, Layout, Mesh, Vestibules.
Function - Will you be using the tent in a summer heatwave, extreme cold, or a mild fall?
Size - From ultralight single man to 10+ person car camping tents.

3 Season vs. 4 Season

3 season tents do well in most situations encountered by the average camper. They are made to withstand summer, spring, and fall weather. Downpours to light snow are generally no problem for 3 seasons tents. Many company's make 3+ season tents for those that foresee themselves regularly encountering a mild amount of snow on their adventures. 3+ season tents differ in that they are made with stronger materials.

4 Season tents are for the outdoor enthusiast that loves winter camping. These tents tend to weigh more due to use of more durable materials. Bathtub floors, no seams, double vestibule, waterproof & breathable fabric are often features you will find listed on 4 season tents.

Single Wall vs. Double Wall

Single wall tents are typically best when doing alpine mountaineering. They need good ventilation and design for proper air flow. Single wall tents require extra care to maintain the breathing capability and durability of the fabric.

Most campers will likely find a double wall tent to be most suitable for their needs due to the effectiveness and ease of use. Double wall tents work but allowing moisture to collect on the rain fly outside of the tent. Single wall tents are often colder than double walls as their isn't a cushion of air to help insulate.

Staked Design vs. Free Standing

Free standing tents can be setup anywhere there is available space. Stakes are usually included with freestanding tents and are recommended to use though it isn't always necessary.

Staked designs are good choice when weight is a concern. The main drawback to a staked design is that tie down rocks or soft ground is required for setup. For the ultralight camper a tarp can be great way to lower the weight of your pack.

Design Features

Vestibules are good for when space is limited and gear needs to stay protected from the elements. Double vestibules are convenient for camping with a partner as it allows for both people to enter and exit the tent without crawling over their partner. It is also possible to cook under your vestibule when conditions are too harsh out in the open.

Mesh is found on most tents as it allows for greater air flow. One of the drawbacks to tents with lots of mesh is its easier for dirt/dust to get in and for warm air to escape when conditions are windy. Depending on the weather conditions you'll want more or less mesh. Generally speaking more mesh is better for warm and dry conditions although dirt can be an issue in the desert.

Rain flys should ideally be made from one piece of fabric to help prevent leakage from seam stitches. Its a good idea to tie down your rain fly as they can become fairly noisy when conditions are wet and windy.

Sleeve or Clip pole attachments are mostly about preference as they both have benefits and drawbacks. The main benefit to clip pole attachments is ease of setup and tear down although they are harder to replace if broken. Sleeves can be a bit more of a hassle to setup but are easier to repair and distribute pressure more evenly across the tent.

Doors are often overlooked when considering what to buy but having a well designed door can extend the longevity of your tents door/zipper. Doors that open from the bottom are best as they keep the door from being trampled on entering and exiting of the tent.

Internal Guylines are great for adding strength and stability your tent. Guylines can double as a clothing line to dry stuff during the day time.

Floor design and material are very important considerations when picking a tent as the wrong choice may leave you and your gear soaking wet. Bathtub style flooring is best for wet conditions as its generally seamless on the bottom to prevent water from entering through stitching. Seam tape is another way to help prevent water from entering through stitches.