The most likely way to ruin your training is to get injured. The fastest way to get injured is to wreck on your bike.
There is one simple tip that can make or break (literally) years of training and racing - Put your weight on the outside pedal when taking a turn.
If you rest your weight on your butt, evenly on the pedals, or on the inside pedal at all, you greatly increase the risk of the bike shooting out from under you if the tires start to slip.
On the other hand, if your weight is on the outside pedal, you have mechanically leveraged the outside of the bike so that it tends to right itself, not falling flat under you like a piece of plywood. Tires slipping simply send the bike out a little wider instead of suddenly surfing your Cervelo into the nearest hedgerow.
You can practice this often. Take a turn, put all your weight on the outside pedal, and let your butt hover over the saddle. You'll quickly realize that you can take corners much faster and safer, especially ones with a little gravel and wet pavement.