How to win a game without opponent blunders?

In the last 10 OTB matches played by me, I won 0, drew 4 and lost 6. The reason for this is because I have basically no counter attack and absolutely no feeling for positional play. Until now I relied on winning a pawn or so and then holding positions, but with my opponents making no percievable blunders, it is impossible to seriously threaten anyone.

When I have enough time on my clock, I play decent, logical moves by calculating every possible line.

However, these moves are only good in the short term.

I have no lsrger strategy, so in many games against strong opponents, I have no attempt of winning, only of holding my position (which does not always succeed)

I need to learn strategy and endgame knowledge.

to illustrate, let us see this game. I was black

or

I was white :

again no attack at all, just advanced pawns and stood (waited to die) . 
(comments copied as were given by lichess engine)

The best way to do it is not to blunder