Most common classroom management advice

So I've been reading up on classroom management quite a bit this summer and one of the most common things I've come across is you can't let the little things go. This is probably my worst area do I'll have to really work on it this year

http://teach4theheart.com/2014/08/11/the-tiny-mistake-that-could-ruin-your-whole-year-and-how-to-avoid-it/

http://teach4theheart.com/2014/08/14/what-not-to-do-the-first-day-of-school/