The training I did was directly related to what i needed to work on. Running, juking (side-step), hitting, rucking, tackling and most kicking i was good enough at as fly-half. My ability to read the defense and make quick decisions (which i still struggle with) were the two areas i needed the most help.
Reading the defense is really hard to practice unless you are doing a scrimmage or actually playing a game. Just a couple experiences in games made me aware of what gaps i should be looking for and how to create/capitalize on them. This comes from experience and watching people better than you.
Watching games at just one or two levels higher than you seem to be the most beneficial. watching the best in the world is hard to help you out because they're so damn good it's near impossible for you and your teammates to replicate what they do.
for the decision-making thing, just be the guy in practice in the position that makes the decisions in each drill. 3 on 2, scrimmage, any other drill you do that requires one man run the show and make on-the-fly decisions at some point, be that man. this is where having someone watching you helps, because you can do what they suggest immediately after, rather than waiting for that situation to occur again in a game.
I was first put in fly-half my sophomore year in college, and honestly i just couldnt cut it. i was a little young, so the older players didn't like taking my direction, and i had a helluva time reading play, so my confidence and morale was low. i wasn't horrible, but i was not producing like i needed to. between that and a need for a fullback, i moved to fullback.
This time around has been better. Me and the former fly-half are easily the two best backs, so it came down to the fact that the other guy is better at fullback and im a bit faster than him, so he went there and i to number 10. Now I am the oldest and among the most experienced rugby players on the team, so when i want to try something or order my other backs to do something, it gets done. with this ability i was really able to run things how i wanted, and it worked well and i gained confidence. at this point, i was a good kicker and tackler, well-respected, good at reading defense and making sequences (light-years ahead of what i was), but still in need of work on the quick decision-making thing, which im working on. My pass also isn't what it needs to be, but im watching the best passer on the team close and it's getting better.
As far as tees go, our fullback got that puma adjustable tee, and for some reason we both were very good with it on the first day. The adjustablility part is good, plus the surface where the ball rests is really good, allowing us to place it at whatever angle we please. this works for us, but there are so many designs out there it's obvious that different people take different approaches in their kicking style, but that's the best ive ever used.
I hope this novel of endless babbling is of some help to you. best of luck, and just relax and practice. those are the two things i would tell myself 2.5 years ago when i tried fly-half the first time...