I play Garen bot lane and be quiet if your one of those people who say Garen HAS to be top or mid lane. For summoner spells I take heal and flash for sticky situations, but know ignite is not a bad choice either. Garen is a naturally tanky champion so use this to your advantage, but don't overdo it, as with any good player you will get ganked so be prepared. e.g. you can use your Q for escape as well because it doesn't need a target also if your having trouble surviving try to get your W as powerful as you can.

If you know Garen you know the legendary spin 2 win, and if you are a little out farmed you can always spin to win in minions faces. Just be careful as Judgement(spin to win) has a fairly long cooldown at early levels.

As Garen you naturally live in the bushes waiting for pray and once it shows up you iniatiate with your Q then E then if you can kill your R.