Stash your bobby pins in a Tic Tac container to keep from losing them. (Brilliant tip!) Pack clothing items around a color scheme (denim/black/white/gray) so that it's easy to mix and match. Dress up your outfits with scarves or jewelry.
How to Pack for a Month in a Carry-On Suitcase - Great tips for packing light. I'm going to try and take about the same amount of stuff on the honeymoon, and use a regular sized suitcase to leave plenty of space for souvenirs.