The strategy game rule I stole from chess and never looked back

Chess players talk about not moving a piece until you've considered what your opponent's best response is — not just whether your move looks good in isolation. I started applying the same discipline to strategy games generally, and my results improved more than any single build order or unit-composition change ever managed.

Most losses I'd been chalking up to bad luck or an unfair matchup were actually just moves made without seriously imagining the opponent's best counter. Once I built in the habit of pausing for one extra beat — "what's the strongest response to this?" — before committing, my win rate across several different strategy games jumped noticeably, independent of any mechanical skill improvement at all.

Related reading: The Guide to What Actually Makes a Game Feel Good (or Bad) to Play.