Really really confused...

Ok. So first off I wanna ask some questions. How do you know if someone is into you? How do you know they have an intrest or maybe think of you more than a friend? These things haunt me and make me wonder. As of late I've been having some superb luck with life and I hope it will continue for as long as possible even though I know it can't forever. but these questions if I can find the answear will make my life easier. Maybe for the good maybe for the better. But if I knew I wouldn't be here asking you guys now would I?