Try making some tracks using just the OT by sampling your other gear into it, or stuff from your music collection or from youtube, working with the eight track limitation. Make destructive decisions along the way, such as choosing to resample several tracks into one. Ignore the source tracks at this point and repurpose the resampled track... treat it as something you sampled off a record... you wouldn't want to leave it as is, so chop that up, add effects, p-locks, and go nuts with it. Maybe even resample those results for further destruction.
An obvious approach when resampling is to group things like drums or melodic parts together, but experiment with sampling different parts together, since you can get some interesting patterns when chopping up those combined samples. I try to get around the static nature of a sampled loop by recording several passes through to capture as much modulation as I can. This also allows for several different sounding slices of the same section of a pattern, which can be fun to work with.
I think by doing everything in the OT for a few tracks, by sampling every component into it to create your track, you will get more into the sampling mindset, which will help you decide what you'd like to sample as you become more familiar. It's a different approach to musical expression so it requires its own practice and dedication, but I find it greatly complements existing skills and is worth the effort.
I don't do it as much as I used to, but it can be a lot of fun to set aside a morning to go through youtube or DVDs or my music collection and doing nothing but sample. With something like the OT it gets hard to resist the temptation to start jamming.
The album I have found to be most inspiring when it comes to sampling, for nearly a decade now, is Panda Bear's Person Pitch, which he made entirely with a couple Boss SP-303s. I started producing electronic music with a SP-404, and the OT is a godsend for that kind of workflow in comparison (which is probably why Panda Bear uses OTs now). What I like about Person Pitch is how there is no programming involved... all the melodies and rhythms come from the sampled loops. I don't think I have ever made a track like that since I usually utilize live instrumentation and drum machines, but anytime I listen to the album I get the urge to do more sample based stuff.
Anyway, hopefully there was something useful there beyond caffeine-induced ramblings. Just sample everything, have fun, and the OT will take you to some incredible places