Ok let me give you advise on how to effectivly train yourself.
Follow the steps one by one:
- Determine at what level of skill you are now, and find out what you do not know about the game, which is always a lot.
- Read article written by knowleable players in the community or even in real life players regarding the topics that you haven't mastered yet.
- Then compare your newly gained knowledge to your decks, and see where you miss out on the nwly gained knowledge in your deck(s).
- Then you tweak your deck(s) to the point that you think you have updated them to your full knowledge of the game.
- Then and onlt then you go and duel people that are either better than you are or are of the same knowledge and game play level.
Then after a few matches ( like 40 ) you can slightly determine if you master the newly gained knowledge and if you actually improved. If not repeat the steps, if so repeat the steps. Until you yourself cannot see the corners of YGO on which you need to improve on.