Capes and masks for dress play? If you can't sew, then you can cut with the shears that are zigzagged (I forget what they're called, but they keep the fabric from fraying) and then hot glue down for a seam.
My sister made my boys towels. They love them and fight over them. It's all their own. She took rags that matched the towels and added a hood and little hand pockets at 2 corners. She just used simple, but colorful towels/rags. It was great. You would have to sew this, but you could do it by hand or machine and it would be simple even for someone who doesn't really know how.
Canvas shoes decorated with paint pens.
Signs for their bedroom doors. No parents allowed, JJ's room, Where I throw it IS where it belongs, etc. You could look around for cute sayings. Shaped wood can be found at craft stores in several sections, they have shelves too! All you would have to do is paint. They also have wooden toys that need painting.
Have fun! I go crazy in those stores and never once considered myself imaginative or crafty - but I have learned so much and love it.