A good sensei can provide these things, but they are rare. This may be a good time to forget adding new things and work on depth. You say you've discovered things on your own - good! Keep on this path. Discover the nuances of hip motion, spring from your legs, relaxation for speed and new body feel. Do your moves a bit differently each time experimenting with these elements.
Conditioning you can do on your own - get creative. Work on tactics, practice combos that feel good to you till they become spontaneous. Visualize an opponent and how he might react and possible counters. Read Motobu (and other masters) and get some idea of old-style karate fighting strategy.
This is worthless training. As has been said by others see things as a beginner. Instead of doing reps 1 ,2, 3, 4..., approach it as 1, 1, 1, 1... doing each one as if it's the first.
Don't stress over things. Keep it enjoyable, or at least interesting.