I recently played 5 online games against a player rated 1700 on the site. I’m not sure what his real strength would be, but he lost all 5 games and made a lot of typical mistakes. They weren’t all tactical though. After losing a couple games to tactical blunders he tried a positional approach but still lost because he made the mistake of allowing me more space and control of the only open file. I thought it would be interesting to see a couple of his typical mistakes.
In this position which we arrived at after some inaccurate play by both sides, we have a common situation where one side has a B and N vs. a R. The question is always which is better? In the opening the two pieces are normally worth a R and 2P’s while in the ending the superiority of the B and N over the R is less pronounced.
Here the P’s are equal so things balance out. For example, if you examine an ending with a R vs. B and N, it is a draw. Give the 2 pieces a P and they win. Give the R a P and it’s still a draw. You may want to play around with these positions at the Shredder endgame database.
In this position White sensed the danger from all of Black’s pieces aimed at his K and realized a sacrifice was in the air so he decided to defend his g-Pawn with: 24.Kh2 but still fell victim to the sacrifice. 24.f4 is a typical defense seen in these types of positions, but it doesn’t work here. After 24…Nxg3 25.Qg2 Qa7 26.Qxg3 Bxf4 White loses because of the double attack and pin on his e-Pawn. 24...Nxg3 Anyway! 25.fxg3 Rh4+ utilizing the pin on the g-Pawn to get the R into the attack. White gets mated because of his weakness on the long diagonal.
24.Rd1 was best because Black has no immediate win. The reason is because there is no pin on the g-Pawn and so no way to get the R into play on the h-file. Houdini gives Black an advantage of 2 and one half P's here (personally I'm not so sure this is the case), but it will take GM technique to exploit it. If White had not walked into the pin on his g-Pawn then 24...Nxg3 25.fxg3 Rh4 isn't playable because there is no pin.
Finally…in this position
White tried to launch a K-side attack before completing his development and castling with 8.Qh4 and after 8…h6 he sacrificed a piece with 9.Bxh6 Even backing down with 9.Bf4 fails because his B which is guarding c2 is undefended so after 9…Nb4 he will lose the exchange. 9...Nb4 Capturing the B allows White a perpetual check 10.Be2 Nc2+ 11.Kf1 Nxa1 Black is up the exchange. However it turned out that I actually missed the best line because I could have safely taken the B on move 11 and then capture the a1 R.
Once again, you need to know tactics, but more than that, you need to realize when they are afoot and when they aren’t! In the first position White did not realize the value of 2 pieces vs. a R and under what circumstances the different combination of pieces are better. In the second position he tried launching an attack before completing his development, disregarded the B on d3 that was left hanging and he did not understand the prerequisites for a successful K-side attack of the type he was trying to conduct.
Two books would help: The Art of Attack in Chess by Vukovic and Attack with Mikhail Tal.