Unless you are prepared to use some of the more exotic materials such as Cuben, it's hard to go wrong with 1.3 oz/yd silnylon for the fly and 1.1 oz/yd ripstop and no-see-um mesh for the tent body. You can get all of this from Quest Outfitters or Seattle Fabrics; Google them, they both have online catalogs. They also stock the clips and buckles and cord-locks you will likely need.
Now, in my experience, it is difficult at best, to duplicate or better what tent making firms have to offer your first time out. You will need to learn by doing and mistakes can be expensive. You will lack the experience and knowledge tent makers have acquired over the years and usually at considerable expense. Please don't think I'm saying you can't make a great tent though. I am saying that you probably won't save any money.
May I walk in beauty.