Hi Mike,
I can sympathize... I was in your shoes last year when I was a new 3rd-year, fumbling around and taking 3 hours to do one sealant.
It will get easier though. The thing is, once you have done a procedure for the first time, you usually realize "that wasn't so hard!"
The next time you do the same procedure you would approach it with newfound confidence.
Since you have already cut two crown preps, it must be pretty familiar to you by now. Cutting preps for an FPD is the same, except you just have to pay more attention to maintaining a common path of insertion.
Doing CU/CLs and RPDs are not very difficult either, for the first two visits anyway (primary and secondary impressions, the 2ndary with border molding). After taking jaw records/establishing VDO, it's pretty much all lab work (setting teeth, flasking, etc.).
Endo is easy after you've done the first one. If you can, get a simple case to start off with such as a single-canal anterior. After the first one you will be confident enough to move onto the more complicated ones, like #5 or #12 (with 2 canals). After that, give a molar a try.
I was afraid of doing anything at the beginning of last year. Now that I'm halfway through my 4th year I've found myself doing things A LOT quicker. Sealants in 5 minutes. A Class-II Amalgam in 40 minutes (with the rubber dam and all the bells and whistles). Crown prep, provisional, pack cord and PVS impression all in one 3-hour clinical period. Perio surgery crown-lengthening in 1 hour. #5/#12 endo in 2 visits.
Keep on truckin'. You'll get there!