Nobody really calculates everything, so practice to guess what opponent will do and focus on that. Then analyze the games to both catch how close your calculation was to being correct if they played on the side you expected, and what motivated their moves if they played somewhere you didn't expect them too. You want to build up the experience and knowledge base of what kind of moves to calculate. Checks, captures and attack is fairly short term and good start to not blunder the game away or miss punishing the same for your opponent. Then you want to look at where you both are strong and the differences in your positions. Most principles will set you up for that. Then if you learn a opening properly they mostly come with a strong idea of this, if they somehow don't you can use the rule of playing in the direction your pawn-chain points. If there is no pawn-chains to follow, the center should be open and wild enough to be where the play is at. Don't bother with the tactics in this regard in the opening, it better to lose to one now and then and remember it to the next time and try to calculate it out each time. Lose and learn, just make sure to look at it afterwards so you really do know to not do that particular thing next time. But we can't stop and calculate or refuse to take a gambit or such, let your opponent show you instead.