I have a text document open to the side of the roulette window with a plan set out with my short term strategy.
Another short term strategy I use is to look at the history of numbers make a note of the most recent number out, the least recent number and the one in the middle, then place a bet on those three numbers including 2 numbers either side and place the same bet amount for 4 spins total. I usually hit at least 2 out of 4. Then after the 4th spin I will go back to the history of numbers and do the same again. Usually play for about 10-20 mins max then come off.