There are many decent books on the topic of how to think during a game of chess. This post is not an attempt to challenge Grand Masters’ advice but instead is focused on how I play chess.
1) Threat scan. Scanning the chess board for threats from both sides is my first task. If there is a threat from the opponent, I think about how to counteract it.
2) Planning. I try to develop a plan by considering strategic goals, namely, piece activity, King safety and pawn structure. Once a plan is made, I focus on sequence of possible moves through which I can achieve my objectives.
3) Calculate Variations. First I prioritize available sequence of moves (candidate moves) and then analyze one by one critically. At the end I select the candidate move with the bright future.
4) Blunder Check. Before making the move selected in step 3, I quickly check once again one-move offensive or defensive disasters.
If all is clear, I made the move.