The thing is you won't win every time. If you play poker expecting to win every time, you are going to be disappointed.
We should exploit loose ranges by playing tight and tight ranges by playing loose (if there are tight players in the blinds, we should steal loosely from the button).
equity win tie pots won pots tied
Hand 0: 57.989% 56.41% 01.58% 150981714276 4234281546.00 { 66+, A4s+, K8s+, Q9s+, J9s+, T9s, A9o+, KTo+, QTo+, JTo }
Hand 1: 42.011% 40.43% 01.58% 108213017190 4234281546.00 { 33+, A2s+, K2s+, Q2s+, J4s+, T6s+, 96s+, 86s+, 76s, 65s, A2o+, K5o+, Q7o+, J7o+, T7o+, 98o }
This is from pokerstove showing the top 20% of hands (our range) against a range of the top 50% of hands. It's fine if it's unclear, I'll explain. Basically, it is showing equity (the chance we have to win) before the flop. So we are a (roughly) 3:2 favourite against this range. So preflop, by playing tight we are going to be winning more money (on average) than our opponent playing 50% of hands (assuming we make less mistakes postflop). The key is learning to make less mistakes postflop than our opponents (in other words we will put in more money with a higher chance of winning (equity)) by narrowing their range on each street and making the correct decision based on that range (folding when our equity is poor, and shoveling money into the pot when our equity is high).
Hopefully, this helps you see how money flows from one player to another in poker (how it can be profitable).
If you have questions, ask away! Everyone is here to help.