Yes, Chess Mentor training and chess.com videos can improve your game with daily training.
I've been a chess.com diamond member since November 2013 and have been pleased with the gradual knowledge and rating increase I've seen since subscribing.
The main perks of the Diamond package are their Chess Mentor and the chess.com video library. You get unlimited access to both. Here's how I'm using them:
The Video Library
Choose a video series such as GM Melik Khachiyan’s three-part “Becoming an Expert” (part 1, part 2, part 3), watch them all, and make quick notes about the key points you took away from each video. Really – take short notes; you'll retain more that way. Skimming through your notebook becomes really helpful too. There is little point in gaining knowledge if you can't retain it.
Every time you find an instructor you enjoy listening to, use the video index to find other courses they've authored and watch more from them — or just write down the name of their course in your notebook under a “to watch” list. Not sure who to start with? GM Melik Khachiyan, GM Ben Finegold, IM Daniel Rensch, and IM Thomas Rendle are all fun and informative. They make me feel good about chess. Melik, Ben, and Thomas are all professional full-time chess coaches, and Daniel's a strong player and one of the founders of chess.com.
Do this every day and you'll soon build up a thick notebook of tips and take-aways. You won't see a sudden dramatic improvement by doing this alone; instead, the idea is to absorb as many opinions, patterns, and maxims as you can. That way, in your future games, you'll have a team of amazing chess coaches in your head talking to you, whispering the knowledge and mantras you wrote in your book.
For example, GM Melik says in his Positional Tips series that, when you think you've finished calculating a line, always ask yourself, “what am I missing?” and make one final check. Hearing that voice has helped me avoid blunders. And, when an opponent plays aggressive chess right out of the opening with traps and fake threats, I often hear Melik’s advice to “stay strong, stay focussed” and repeat it to myself — a defensive mantra of sorts!
Chess Mentor is a fabulous tool — it forces you to play through the lines by moving the pieces as well as visualising the sequence, explains why you went wrong, cheers you along, and flows onto the next challenge automatically.
Use it every day for an hour if you can alongside tactics training and video watching. You can pick out an individual lesson that takes your fancy, or follow a more thorough Chess Mentor course by an author you like. You can also repeat lessons to drill them. For example, I did the opposition drills several times, and have found I'm winning more endgames now. I knew the principle of opposition, but it was only by practising it — by actively moving the pieces on a board rather than reading a book describing the sequence — that it sunk in.
Don't forget to bookmark your chess mentor rating page to keep an eye on your progress report and encourage yourself to keep going.
Not a replacement for playing slow games
Of course, while I've really enjoyed Chess Mentor and the videos on chess.com and ICC, if you want to get good faster, the things that have helped me so far are to:
- Play lots of slow time control games, where you have time to think and find the best move every move. (Blitz is okay too, but most instructors will tell beginners and improvers to spend about a tenth of their time playing blitz as they do playing chess at longer time controls of 45 minutes or more.)
- Review those games with your opponent, a computer, and a teacher.
- Identify and correct flaws in your thought process that caused you to lose your game. (e.g. “I forgot to identify my opponent's checks, captures, and threats before making my move. In the future I will always think, ‘checks, captures, and threats’ before I play my move – every move.”)
- Become really disciplined in your thinking process.
- Play chess in two modes only: you play your best move every move, or you resign. (A tip from Dan Heisman.)