Best material to create designs on fabric?

Hi! i want to sew on designs into fabrics...like little birds and other such animals...im making quilt sqaures about 6 by 6. my question is, what fabric should i use, and what thread? also what different size threads should i use, since some thread i would like thin and some thread i would probably want thicker thread, so what do you guys say? im thinking of usuing cotton fabric? unless thats not the best? thanks in advance for answering!