The Chess Club and Scholastic Center of Saint Louis posts really instructional videos on YouTube, definitely worth checking out: Chess Club and Scholastic Center of Saint Louis
Chessable is a great tool for building up your own opening repertoire, or practicing endings etc. In their own words "Chessable aims to make learning chess content as easy and efficient as possible. " It uses spaced repetition to make you remember everything better.
Forward Chess provides interactive chess books, allowing you to read books and play through games and positions in the book via an app on your phone, tablet and computer.
For tips on what books to read, have a look here: Books
For the BCCTM (Beverley Chess Club Tip of the Month), click here.
Our very own Gerry Johnstone has written this useful article on How to avoid making blunders
IM Silman writes very good articles. Here is one on the creation of weak squares: https://www.chess.com/article/view/i-m-passionate-about-squares