Making a t-shirt ?? Urgent help needed !!?

Think simplicity, and as for fabric, definately cotton, for ease and for children it is just a smart move. For design, maybe Try an A line t'shirt that goes out like a little skirt in stead of straight down like a normal t'shirt. Think little girl , darling girly features maybe one cute little bow, maybe at the back at the top of a gather, or a A ruffle at the bottom of the shirt or shorts, or satin trim. Simple little darling features for a Little girl under 5 is the way to go, don't over do it then it gets unattractive, pick some Sweet pastel pinks purples, yellows even whites. If you do the pooh decoration, keep it small not too big maybe on the sleeve or the corner of the bottom of the short, the whole Idea to catch peoples eye on little girls clothing is keeping it sweet and girly. Hope I helped a bit.