Not only is joey right about learning how to recognize before PLL, but you can also recognize your AUF from one side, so look at a side that's not being moved during the last 2-3 moves of the alg.
More importantly, a small kitten is also very right: learn how your algs work and practice.
You should know how your PLL works, so you can avoid AUF + cube rotation + AUF.
Edit: Just to point out: You AUF + cube rotation, for both R perms (if you use the common algs anyway) and the Z perm have an AUF. Any alg that ends in U, U', or U2 at the end is counted as an AUF.