Doing skills in FIFA is going to be tough using a keyboard... With a controller, all of the tricks are done by using L2/LT in conjunction with the Right Analog Stick (sometimes Left Stick movements too).
This means that it is almost impossible to map keys to the buttons and perform the tricks, especially ones where rotations of the stick are needed, unless you like playing Twister with your fingers on the keyboard
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I suggest not doing the skill moves but instead just using the stuff that can be done easily by just holding buttons (I'm using console buttons here, but you can map them to keys);
L2 + Direction = Close control
L1 + Direction = Precision control
L2 + R2 + Direction = Skilled dribble
You should definitely invest in a controller though - it will make the game much easier to play as well as letting you use the 360 degree dribbling (keyboard is 8 direction max).