Hmm. I suggest solving simpler puzzles (lets say out of the group you can get at least 80% right) untimed. Go for accuracy. Write down your solution and write how much material you will be ahead at the end of the calculation.
Do this every day for a month, and you'll build some good habits.
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During a game, immediately after your opponent's move, you need to calculate short sequences of forcing moves (checks, captures, and threats) to see if you have a tactic. You just have to discipline yourself to do this (although solving tactics for accuracy will help put you in that frame of mind).
Even at very high levels, although it's more rare, the strategic dialogue distracts players into not checking all the threats and captures available. Make the first 30 seconds after the opponent's move (or however much time you need) dedicated to calculating short sequences of forcing moves. No strategic thinking. Imagine the opponent made the move and asked "is this a mistake?" Try to punish the opponent's move and you can answer that question.
Only after you find no punishment can you start up the strategic dialogue again.
I'm still pretty new to chess. I've been playing for 1-2 years, but I have mostly been analyzing games and studying some positional concepts. I've found, having returned to playing a lot, that my discipline in calculation and tactical awareness is shocking. In the pro games, they are just aware of all potential tactics all the time, but I often fall to really simple tricks etc. and miss easy ways to get a serious advantage after an opening blunder. My tactics tend to be really inconsistent. Sometimes I will see a tactic and other times I just won't.
I've also found that I don't calculate nearly as much as I should. Say I come up with some basic positional and strategic moves, I then just seem to calculate maybe 1 line and then just play it instead of really looking at what they're going to play (again, because I don't really know what I'm looking for).
I know that no one starts off calculating everything and being aware of all potential tactics, and I also know that no one who knows what they are doing would just play 'hope' chess. I was just hoping someone could help me out with how to become more disciplined I guess. I have John Nunn's chess puzzle book which is pretty advanced, and I can manage to get quite a few puzzles from 1-3, but in game everything just goes to poo for some reason.