I dont just move my keeper a tad, i take full control and actually press square to make a save.. And id let in about 1 in 20 due to stuffing up.
so..
1. at freekick, i take manual control of my keeper. But leave him where he is and dont move until the kicker is just about to kick - otherwise, if you move to one side too early, the fk taker simply goes to the side of goal most open.
2. just before fk taker kicks (last few steps.... not too late though, otherwise you wont stop the really powerful kicks... you have to time it), i move my keeper to the most open side of the goal, ie. the end the fk will always go for. I hold the stick in that direction, and press/keep tapping the square button. As a result you are saving with keeper manually (even though the keeper would probably still save automatically if ball goes directly in line with him). The benefit in this method also includes the wall jumping... ie. the square press not only manually saves as a keeper, but also makes wall jump.... In fact, many times i do this, the wall actually jumps and stops the ball from even reaching my keeper. Guess it also depends on fk taker, and how good he is at getting it over the wall. Either way, my keeper is there waiting and usually saving.
Note: i did concede one yesterday, as I just wasnt quick enough with my keeper compared to how powerful a kick the fk taker was... some really good fk takers make it it more difficult due to power alone.