Experience From - John Liebeskind, Karl King, Matt Mahoney,
In addition to Shawn McDonalds tips I would like to emphasize that it helps me to plan my time before I hit the aid station. I try to list in my mind what my objectives are and how many things I want to get done. That way I am less likely to forget something. Often, in my attempt to shove food down towards my churning stomach, I forget important things. I have left aid stations a few times after forgetting to Vaseline up and left to suffer until the next station. (I guess I should try that Body Glide stuff.) If you have a crew, or if the aid station workers are good, you can just list your needs when you get there.
Adding to the excellent posts preceding, if you're new to the course, ask the aid station people about the nature of the upcoming section, and if there are any difficult spots. The aid station people may not be familiar with the course, but it they are, their advice may save you trouble, or help you apply the right strategy for the section. Especially when it is late in a run and fatigue is working on your mind, it is helpful to know what is coming.
Example: Mountain Masochist 50+ miler. The sign at a late aid station said only 4 miles to the next stop. "4 miles, no big deal, just fill my bottle half full." The station guy replied,"Uh, you better fill it because it runs like 7." Happily, I took his advice and was glad I did because it ran like 8. Ah, the joy of Horton Miles.
All this wonderful advice on aid stations. Here's some more:
DROP BAGS: Forget 'em. You lose an awful lot of time fiddling with them when you should be on the trail, not to mention fretting before the race about what goes in which bag. It's so much simpler to just start with everything you'll need. At the aid stations you can just fill your bottles, grab some food and get out.
Last year at Leadville when we had near-freezing rain all day, a lot of people DNF'ed because their warm clothes were in the wrong drop bag. Since I flew to Colorado for 2 weeks with just one carry-on bag (including camping gear), I couldn't afford the luxury of a complete change of clothes and shoes at every aid station. I started with nylon pants and jacket tied around my waist and a space blanket in my fanny pack (with a hole cut in the middle, reinforced with tape, for my head) to use as a raincoat. I didn't plan to use them during the day, but plans can change.
Last year I had 2 drop bags but used only one. This year I just had one and didn't use most of what was in it. Leadville lacks protein at the aid stations, but the 2 tuna and cheese sandwiches I started with would have probably gotten me through the whole race without the powdered milk from my drop bag.
As for crews, its nice to have one, but if you aren't prepared to finish on your own, a crew isn't going to help you much.
A Link - Shawn MsDonalds Tips For Aid Station Use/Planning located on another web site.