Ok, you can do those colors as your theme, or you can do something else but that would be easy to find things for. We did this sky blue color for my SILs shower and it ended up being such a pain! So you're looking for decorations?? I made that wreath recently that i LOVED, and everyone thought it was adorable. It just depends on what activities you have planned, how much space you have, how many people you'll have that will effect your decorations. I'm THRILLED to help out. I love doing stuff like that and I'm pretty bored right now being at home just waiting on Tyler to get here!
You can also have your food match your color scheme which is fun. I'm just not really sure where to begin. Have you looked at invites you like? Sometimes that will give you inspiration as to where to start.
these aren't too springy but good for the pink/brown colors if that's what you want:
Girls Baby Shower Invitations - Fancy Florals by Mixbook
love these:
Baby Shower Invitations - Little Hoot: Ballet by Tiny Prints