Stick to the basics:
1. Evaluate the pawns
- both yours and your opponents - how can one side improve, or be weakened?
e.g. isolated pawns tend to be easy prey, but if advanced far they can become dangerous!
2. Check for unprotected pieces
- perhaps more obvious, but sometimes an opponents (or your!) knight or Bishop
could be tucked behind a pawn, seemingly safe, but yet is doomed, like in the diagram below:
White to play
You'd be surprised how many people miss moves like Nxe4, which in the end wins a pawn.
...Also, be sure to double-check, and perhaps even triple-check a move before actually making it.
3. Measure King safety
, and check all checks accordingly!
- The last thing you want during your attacking combination
is your opponent to have a move with check, potentially winning material... and on that note:
4. Don't worry too much about material
- there's also time/tempo, space, and all of the above to consider!
Battles are not decided by the size of the army, but by how well the soldiers operate 😉
and of course
5. Keep having fun
🙂 - sure you want to improve, great, but don't let the game frustrate you.
Playing whilst in a bad mood, or with distractions around can ruin a good game.
There's been some good points made by others also, and it's true that there's no substitute for experience.
Play more games against better opponents, experiment with different openings,
and by all means do some [theory] homework if you really want to see your rating climb.
Three years ago all I could just about manage was knowing how the pieces moved, and spotting basic one-move threats,
but look at me now...
Still dropping pieces occasionally and missing mate-in-two's 😀 You can never stop learning!