Active Wear
Active wear is largely going to be dependent on the weather where you are... being active. Different times of year will call for different clothes due to the changes in the weather patterns.
Summer is typically hotter weather, can be humid depending on where you are. It can be tempting to just cut back on the amount of clothing, but it is important to keep from exposing too much skin, due to burns, allergies, bugs...
You will typically want your undergarments and socks to be breathable and allow a lot of air flow. You will likely be sweating more during these months meaning that moisture wicking shirts and pants will be very helpful. And of course you want to keep in the shade, so a hat is very important.
Just because it is hot doesn't mean you want shorts and short sleeves. You may want to have pants and long sleeves if there are a lot of mosquitos or irritating plants in the area. You can find many items with pit-zips (zipper openings in the armpits of shirts) or mesh to allow for more breathability. There are also shirts that have SPF protection to keep you from burning. And don't forget the swim suit and sunglasses.
Spring and Fall are a bit on the cooler side, depending on where you are camping, but also can come with a lot of rain and wind. Largely you should be looking at similar clothing to the summer, but keep in mind rain and wind resistant jackets and hats. You may need more coverage in the morning with some gloves or thicker socks. In general you may want to start looking at base layers, but lightweight, nothing too thick or warm.
You will likely want to keep your feet as dry as possible. Waterproof hiking boots and gaiters may keep you from having to dry some socks over a fire.
If you are in the south, you may not need much warmth, but if you are camping in spring near Canada you will want to be on the warmer side with a light puffy and possibly some snow pants.
Then for the cold months. You will want to start paying close attention to layers. You will want to start with a mid to heavy base layer. A warm mid layer along with your puffy or snow jacket to keep dryer. Again you will want to remain dry and will want the moisture wicking clothing, waterproof boots and gaiters, along with possible snow shoes.
Depending on where you are going, you may want to consider crampons which give you spikes on your shoes to keep traction in the ice.
Don't forget your head. You will want ear protection, beanie, neck gaiter to keep as much of the warmth in. The sunglasses are important here as well. Especially in areas with lots of snow you will want to keep the bright toned down as much as possible.