I don't tend to use healers as you go up levels people have good air defence & air balloons/bombs
I would just go with healing spells but don't use them to early about half life is good, also timing is everything send 1 giant as a dummy once a mortar has hit him send your Wallbreakers as they will avoid getting hit then. Once the wall is broken send all the giants.
I wouldn't bother with lower level wizards either take to long to make, either more giants, barbs or archers. While your giants are working away you can send you archers in once the first mortar has gone to help out, don't forget to check the giants health use a healing ring if needed. If you have rage spells those are also good.
If your into looting though just take about 4 Wallbreakers, 5 giants & the rest a goblin/archer/barb mix. Lose a few trophies but make loads of it.
There is a lot of ways of how to attack etc though just about finding one your comfortable with and is effective for you. It helps upgrading your army camps so you can hold more.
My usual is 15 giants, 4 wall breakers and the rest archers/barbs. I've got lvl5 troops though I'm also mainly a looter so I don't bother with troops that cost to much or take to long to make. That said clan wars is a different story!
Also make sure your not in a league which is to hard for you, what level are you? Sometimes it's better to drop 1 or 2 leagues you get easier targets and easier loots. Pick easy targets who have open bases where it only takes 1 wall to reach everything.