The first troop that you will get in clash of clans is a barbarian, who does 8 damage per second and costs only 25 elexir. Then you get an archer, this is more advanced, it only does 7 damage per second, but costs 50 elixir, this is because it can throw arrows at objects near the wall. You can then get, at a lv 3 barracks, goblins. These gobs like to take resources so they do 11 damage per second. Know you may think that these are awesome.They aren't for one reason, they target resources. This means that they will prefer to take all the resources in the field and the town hall, and then go to the defenses. Essentially this means that they will die out and won't be able to do any major damage. Then you can get, giants, wall breakers,balloons, wizards and many more, which are better.
The most popular at the moment battle strategy is to put in 10-15 giants and 1 or 2 healers, this will help you destroy the defenses and then send in the archers and barbs, but if you don't want any archers or barbs then just attack will 10-15 giants, 2 healers and a dragon. One of the dragons disadvantages is that it does everything very slowly and attacks everything it finds, not only defenses. So in my opinion the best attack is some giants, a healer or two and some drags. But the drags have to be lv 3 or more because then they are too weak and will die easily.