[guineapig]

Start super easy and gradually work your way up.
Don't be embarassed to start by killing greens with your charmed pet to get an idea of how long your charm lasts, how strong the pet is, etc.

Find outdoor areas, close to a zoneline. Know the pathing of anything that might aggro before you start. Tons of good places to practice all over the world.

Once you get the hang of greens, do light blues, then blues.

Stuns are your freind!

The aoe short duration stuns combined with the whirl till you hurl line will help you reestablish control. Have a minumum of 2 of these up at all times. get in the habit of retashing before you recharm.

Use troll form to regen if you are soloing. carry bandages and skill up at bind wound.

Don't be cheap, use your AC buff, your lower level rune and even berzerker strength until you feel comfortable enough without them. You have these damage absorbers for a reason.

rooting the mob that your pet is attacking is a good habit so you only have to deal with 1 mob trying to interrupt you when recasting charm instead of 2.

Best way to start charming is to get your gear squared away first then find a group that wont mind you messing with it. The additional DPS can be huge and if the group has a backup healer then keeping you alive should not be an issue.