I do strength training, for sure. Lots of basic strength lifts, neck work, and grip work.
I obsessively watch technique videos, and make lists of techniques that I want to play around with for that day. Like yesterday, there wasn't anybody in the gym, so I stood a huge foam roller in the middle of the mat and practiced Imanari-style inverted shots.
I also try to roll with more experienced guys as much as possible. Cross-training in sambo and judo has made a huge difference, too.