I have been playing a lot of chess recently after not having played much in the last few years. My rating (sorry, I don't know which rating systems) on most chess websites and so on tends to sit comfortably in the 1400-1500 range, but I can't seem to break that. On various tactics trainers, I seem to able to reach a tactics rating of around 2000 or sometimes higher. Again, I don't know how useful these numbers really are, but if I take them at face value then it would seem that tactics are not my problem. I also think my grasp of strategy is not too bad, I am quite aware of outposts, open files, weak pawn structures and so on and they tend to drive my moves in my games, more so than tactics I would say.
I have a couple of questions to ask regarding improvement here. Firstly, I play a lot against computers, since I can just play a game on my phone without worrying about internet connection. Is this a bad idea if I am trying to improve? The computer I play against seems to be totally brain dead below a rating of about 1300, then suddenly above that rating seems to make almost no blunders. It makes plenty of strategic errors, (advancing way too many pawns early on and stuff like that) but it just seems to be able to plug every hole so quickly, even though it creates a lot for itself. My question is: is it a mistake to practice against computers, given their somewhat erratic way of playing?
I think my game is okay in most areas, and I feel like it could be one or two crucial weaknesses that are holding me back. My opening and end game skills I think are adequate for the level I am playing at, but my middle game seems to be remarkably uninteresting. I can notice where the most important squares are and tend to avoid any big blunders, but against computers the games tend to seize up in the middle...they are just really dry in terms of attacking opportunities because the computer has got it all covered, and I can't create strong threats as quickly as it can defuse them.
I think this may be the big gap in my game. I can solve tactical puzzles quite easily, but I cannot consistently create those sorts of positions that appear in the puzzles in my own games. So my second question is: is this a common pitfall in players around my level and, if so, how do players usually break through this?
Thanks for any input, and sorry for the life story. :)