I usually run fartleks in a few different styles:
1min hard:1min easy (hard periods at about mile effort) for 20 minutes total
2 hard:1 easy @ sub-tempo effort for 4-6 miles
2x4min @tempo effort, 2x3min @5-10k effort, 2x2 min @ 2mi effort, 2x1 min @1mi effort (all with 2min rest)
what kind of pace should I maintain for the rest periods. I generally do a pretty slow jog in between to try and get recovered for the next fast section. These are usually comfortably hard sessions for me. Should I run faster rest or change these up majorly?
I do these kinds of workout in my base training for both xc and track