The cryptic definition is a kind of riddle. The setter is a riddler attempting to misdirect you. Your first reading of the clue may well be the literal one and if so it will definitely be the wrong one. I struggled with the following clue for so long that it has burned itself into my memory as the archetypal cryptic definition:
3. Where people go to make pots on wheels (6)
I still couldn't get clay pots and pottery wheels out of my head when someone came along and casually filled in CASINO while I'd gone to empty some ashtrays. (You could smoke in pubs in those days - it was a long time ago - it still hurts).
Misdirection is the key to a cryptic definition. When you read the clue first - you are put in mind of something that is not the answer. Try to avoid the initial literal meaning of the words, what else could they mean? In the example above, forget potteries. Where else could pots (of money) be made on (roulette) wheels?
Have a go at these:
3. Release John (5)