Make them look full. Same with pockets on Jeans for male figures. Put a wallet sticking out. Have a watch chain hanging out. For women's pants, you don't get near the fun.
People have pockets to put things in.
Don't overlook that detail with your figures. The best one for our purposes is catalog number jt-6, and it has planes dials from WW I and up, and also has cars and boats. Bingo, instant Instrument Panel without having to do any strange painting of such. I recomend photocopying the sheet before you start the project, so you have extra copies. Find this at any RC Plane shop.