My favorite gambit (because I only know 2 :/) is the Blackmier-Diemer. Problem is, the gambit isn’t often accepted by lower level players and is hard to maneuver if it’s declined. Anyone have any advice on this gambit or any other gambit that a player around 1000 could use to easily gain an advantage?
Q+A for beginners(and everyone else)

I want an aggressive repertoire, can annyone give me suggestions for 1500 rapid rating? I gave up on the ruy lopez because of the old steinitz defense d6, its just too frustrating and the phillidor has been quite annoying. I was playing the italian game but don't know if I'm comfortable with the center attack variation as it might not offer much for me. I gave up on the Sicilian and have been playing e5 recently.

As a beginner, is ever better to play the my best opening or is better to test and experience a plenty of different openings?

As a beginner, is ever better to play the my best opening or is better to test and experience a plenty of different openings?
There is no best opening.
My advice is learn the italian.

Is water wet?
It depends on the context.
If you are drunk, high, have phatamorgana mirage, no.
If you are ok, yes.

Can somebody suggest a good tactics book for a 1300 rated player? I am almost done with "Winning Chess Tactics" by Seirawan but it does not have nearly enough problems.
Here are some reading possibilities that I often mention:
Winning Chess by Irving Chernev and Fred Reinfeld (1948)
https://web.archive.org/web/20140708093415/http://www.chesscafe.com/text/review919.pdf
Back to Basics: Tactics by Dan Heisman (2007)
https://web.archive.org/web/20140708233537/http://www.chesscafe.com/text/review585.pdf
https://www.chess.com/article/view/book-review-back-to-basics-tactics
https://static1.squarespace.com/static/5856bd64ff7c50433c3803db/t/5895fc0ca5790af7895297e4/1486224396755/btbtactics2exerpt.pdf

You ask questions, I give answers
Look through my games and find some recurring mistakes. Can you find any?
Dig through my 4000 games, analyze them, and help me construct a structured study plan on how to become a master within the next year, as well as a detailed summary of my current weaknesses. How about no...
How do I move the horse?
Two Squares in a direction and one square over. Commonly thought of as an "L" shape.
https://www.chess.com/learn-how-to-play-chess#chess-pieces-move