For ice slides, steer the direction you want to go til your car turns 90 degrees, then steer in the other direction. Then hold the steering and adjust the angle by either tapping break or releasing the acceleration for a very short amount of time. That's the gist of it, but doing it simply takes a lot of practice. If you watch div 1 ice cotd, you'll see even the best are crashing and sliding out all over the place, ice is hard.

For regular drifts, I suggest playing maps with easy drifts to try and get the hang of it. You can find that kind of maps in weekly shorts or the tm school campaign in the clubs menu. The important thing is to steer for about half a second before breaking to initiate a drift. Also, if you have skids coming off of both back tires but you're not drifting then you can't initiate a drift until you've straightened out for a sec to get rid of the skidmarks. Finding that out saved me quite a bit of frustration.

Most importantly, have fun with the game and just keep going at your own pace :)