Good luck learning; it is a long process and you can always get better.
I recently started playing again after 3 years due to the birth of my 2nd child and have been going
back to my fundamentals a lot. For what it is worth, here are some fundamental tips I try to keep in mind every time I play that may help:
1. I played for my whole first year going through swings up and down before I finally got good enough to
break out of this cycle. It is not enough just to be a "good" player, you need to be good enough to beat the table and the
rake. The more hands you play, the thinner your overall
edge preflop (the more you will rely on
post flop skill) and the more
rake will eat into your expected
winrate. Think about the
rake as part of your poker strategy (i.e., if you blindsteal and everyone folds, most sites do not charge a
rake).
2.
Heads up, you are playing the person more than the cards. As the number of players increase, the more you are playing the cards and calculating odds. What hands do
well with less players (
reverse implied odds), what hands do
well with many players (good draws)?
3.
Position rules, especially in NL. You can play a wider
range of hands
in position since you have the advantage in hands that miss. If you find you are calling OOP waiting to "see what happens on the
flop" you are bleeding money and should
fold preflop. Unless it is a multiway
flop you will not hit enough to make the
call profitable.
4. If you are reading books or articles (there are many great articles on this site as pointed out above), always keep in mind the context of the books or articles. Moves that may work with one
level or player may not work in your circumstance. Understand the "what" but also the "why".
5. Consistency is important. Learn to manage
tilt, it is a part of the game. If you are on a losing streak, look
back at your hands to see what happened. If you were
ahead and got sucked out or had good
equity going all in, fine, but if you go all in or called down badly beaten, you need to re-evaluate your play as you probably found a
leak.
Again, good luck!