Game Resources...Updated
Make your opening game stronger.
This will strengthen your starting game (openings). The thicker lines are the most common moves.

www.thechesswebsite.com/chess-openings
- which has videos (mostly free) and openings.
https://www.youtube.com/channel/UCa2Ezoefyh5Gm9gXwg0kCdA
- this guy has very good videos explaining different openings.
Analyzing your games
lichess is a pretty good resource for puzzles and training. The link above will allow you to copy a game you are playing (say from chess.com).
Copy your moves and paste them in. Then play the rest of the game against the computer and that way you can see what works and what doesn't.
Chess Software
https://lucaschess.pythonanywhere.com/
This program is free and has heaps of options and you can set an opponent from impossible to very very easy.