No matter how large you cut the eye holes, it's still hard to see everything. Then you have the crowds and the noise. No matter how loud parade-goers scream, it's so hard to hear above the dull roar of the tractor and the other crowd noises. It's very hard to see you if you are up really close, so get to the back of the crowd and get the rider's attention. Then come up close, if you must, to get the mother lode of beads.
Signs are a wonderful way to catch the attention of a friend who is riding.
If there is a group and you want to make sure the rider nails you with a ton of beads, send someone a couple blocks ahead to get the rider's attention and show where the group is. If you know where you are going to be, tell the rider so he or she can be on the lookout for you. And finally a little bead etiquette. If a float rider gives you beads, don't keep hounding him or her. I'll keep my eye out for you.