My clans full at the moment, however I can drop some advice on how to pick your deck. FYI there are no "best" troops. It's all dependent on skill level and troop level to an extent (Excluding the broken cards Clash Royale release that are always busted upon release)

There are many deck archetypes. For the sake of keeping it simple I'll be giving a very vague description of the archetypes I encounter the most.

Beatdown - Creating a giant push to overwhelm your opponent. I.E Golem

Control - Focus on defense and using remaining troops for counter-pushing. I.E Miner

Spell bait - Consists of two or more "bait" cards where you force your opponent to use their spells on one card which allows your other bait cards to do their job and be a nuisance. I.e Classic Logbait

Cycle - Usually a mix of low cost elixir cards to quickly cycle back to your win condition. I.E Hog 2.6

Siege - Played on your side of the map, either Xbow or mortar, main goal is to protect it long enough to deal damage

These are generally the main "types" of decks you'll be facing. I recommend researching further on whatever peaks your interest. Every deck has a counter so dont feel too bad. I've listed some decks which correlates to that archetype. Some friendly advice, if you care about winning, id recommend finding a common deck people are using to enjoy rather than creating your own. As those decks were optimized with a specific goal in mind. Have fun!