When I did my 3:24 I did the following track work:
6x1000
4x1600 (3x1600 if it was over 90'F). It was good mental stamina so once it cooled off in October I felt like a beast.
8x800 (Yassos, but only as a check to see where I should be approximately). I started them off in May running 3:40-3:45 but by September they were averaging around 3:15-3:20. I ran 3:24, so not too far off.
I did tempo runs like normal and long runs. I was able to recover from 20-milers fairly well. I did 2:36, 2:40, 2:44 for my 20s and 2:51 for my 21. The 2:36 was my best workout. I ran the last 10 in 74 and felt like I had more to give. The others I ran at easier effort. The day after I'd still be able to do 3-6 miles EZ (8:55-9:20 pace due to heat) but I didn't care. Those EZ runs really do take the lactic out from your legs and make you much fresher. I just don't look at the watch until I'm done.