For freekick it is usually right foot right side, but there could be exception. The announcer will tell you "not his favored side" when he try a freekick.

Using right-footed player on the right side is better at shooting, while using right-footed player on left side is better at dribbling.
Taller and more heavy players have advantage at heading and shooting, while smaller and agile players have advantage at dribbling.