A good start may be buying "Basic of R/C Model Aircraft Design" by Andy Lennnon. It's not an expensive book, last time I saw it on amazon.com it was $19.95 or something like that....And yet is a very good book for introduction to the basic concepts of aircraft design and aerodynamics....It's not heavy on math and explains quite well several aspects....Another book that goes further into aerodynamics is "Model Aircraft Aerodynamics" by Martin Simons, but I don't have this book yet, so I can't comment on it....But I heard it's very good also.

Hope this helps,