I'm horrible at packing

Despite the fact that I travel more than the average bear, I pretty much suck at packing. I just packed an entire suitcase that includes stuff for 3 days of conference plus a social weekend. Here's a list of thing I figure are not in the suitcase yet...makeup, flat iron, jewelry. Here's what I have too much of...EVERYTHING ELSE! I think I packed 4 pairs of shoes plus the pair I'll wear tomorrow. Alarm is set for 5:50am, because I know I'll just want to un-pack and re-pack in the morning. I wish I could go back to my Euro packing days. So long as I had a black fleece and a decent looking top and a rain coat I was good to go! I used to do weekend trips with a backpack. We're not talking a hike through the woods type of backpack. It was just big-ish school backpack. Now I have to worry about multiple scenarios. I need outfits for bumming around town, for going out on the town, for casual nights on the town, for pool parties, and for conferencing it up all in one suitcase. Easier said than done! I hate packing.