I just dropped three games in a row against lower rated opponent. The first one, I was a full queen up!!! I just couldn't find the way to mate.. That really tells you my true level as a chess player. (Although playing at 3am in the morning with my eyes barely open doesn't do any wonders for my game. And yet, I feel as if I should retain enough presence of mind not to blunder)
Full queen up - Yuck!!!
And yet, I then turn around and defeat two 1800 players in fine sacrificial style.
Game A - Bishop sacrifice - I blundered twice and yet a win.
Each time, it gets easier than before as the lines to calculate takes on a familiarity.
I really recommend the 'Art of Attack' to anyone interested in sacrificial chess. Extreme familiarity thematic attacking patterns and the common defensive and offensive maneuvers that occurs during such attacks could take your chess into heights previously unimagined.
Game B - Kingside attack - A nice calculated attack. I foresaw most of the lines.
No more. Time is of the essence
As Nimzo said - "if chess is like a race how foolish it is to stop and rub your nose while in the middle of it."
I particularly enjoyed the last game. At least at a cursory glance, Nde3 looks like a strong attacking idea, and after exd4 the unfolding attack looks very well-executed.
As for the first game: yes, there were many blunders, but I don't think your endgame qualifies as a blunder proper. Queen versus pawn on the seventh rank positions are tricky and are in fact "officially" drawn if your king's far away from the action and you're dealing with a rook or bishop pawn, which gives Black stale-mate tactics White can do nothing against.
In this case, however, I think the endgame is winning for White because White's king's already closing in. But it's still tricky: After 54. ... h2 (which I think is the correct move) 55. g8Q (also correct) Kf2 (what else?) White misses the winning shot 56. Kf4! If (A) 56. ... h1Q 57. Qa2+ Kf1 58. Kg3! and it's either mate or losing the queen for Black. And if (B) 56. ... Kf1 57. Kg3! h1Q 58. Qc4+! or 57. ... Kg1 58. Kh3+! (once again the king move wins; if the queen moves, Black has some annoying defenses by promoting his pawn to a knight) Kf1 59. Qg2+ Game over.
Now this was my morning coffee analysis and I can't say for certain whether it's 100% sound. Long story short: queen versus pawn on the seventh positions are not that easy, and often officially drawn.