Unless you are planning on playing some of the toughest games in the world most of the money that you will win in poker comes from beating bad players. This is even true at the nosebleed levels as games rarely go nowadays without at least on giant spot at the table.
Because of this, especially at the midstakes levels, you should really concentrate on being the best “fish fryer” that you possibly can be since that is where ninety percent of your money will come from. Work on optimizing your lines against these weak players and sucking up all of the money that is possible. Often times players concentrate on the wrong thing—that is they spend way too much time and mental energy paying attention to the other good players at the table. Why would I want to mix it up with someone else who is a big winning player when all of the dead money that we are fighting for comes from the other players? Those are the players that you should be paying attention to the most, as they are the ones that are paying the bills.
This is especially true if you are playing $5 dollar big blind cap games and below. There usually will be only one or maybe two other good players at the table. The rest will be recreational players just waiting to give their money away. In these games it is a race to see who can extract that dead money first. Spend your time studying the bad players. What are their tendencies, what are their patterns? Do they give off any tells? Do they play in a different manner when they tilt? You will find that if you get really good at beating up on the bad players you will achieve a top win rate at your level.