Novice Strategy

As a total beginner, I'm a long way from developing strategic thinking.  It's nearly always about immediate tactics.  But I do need some basic level 'game-plan' to guide my play, and the pattern below seems to be what I've intuitively fallen into.  Can more experienced players give their assessment on my 'strategic' habits, and offer any suggestions for improvement?

Opening Phase as White - safely develop minor pieces, control centre, castle

Opening Phase as Black - disrupt white's memorised opening, develop pieces, castle, stop white controlling centre

Mid-Game - don't blunder, then exploit an opponent's blunder to get material and positional advantage, then quickly simplify through trades

Endgame - remove remaining pieces, promote a pawn, checkmate

Thoughts?

Is simplification a decent goal in the mid-game (when you're ahead)?