A nice write-up of where you believe your skills lie.
I was going to go with a more caveman-like "I look for weaknesses and I start hitting them with a stick".
Jokes apart, I always tend to look at "why people win" through a "Steinitz-Laws" filter -> I win only when
- I can outplay my opponent in critical positions that require accurate moves.
- I capitalize on mistakes made that swing the position to my favored side of the evaluation number line.
- I maintain the position I am holding (and the corresponding evaluation) better than my opponent ... i.e. do a relatively better job at not making the position any worse for me with each move.

. It never happened to me, usually it was plain tactics in the middlegame combined with a little positional pressure. When I lose though, I think the positional misevaluations prove more critical. Still, a vast majority of my losses are from tactical mistakes too. I guess all this is subject to change as I face stronger players.
Do you usually win because of your attacking skill, waiting for your opponent to overextend, or maybe just because your opponent blunders before you?
I post this because my winning strategies I think are unique and even go against common chess advice, like "endgame is most important", "don't study openings", etc.
I usually win because of my superior positional skill to most amateurs I play. This mostly comes from studying the middlegame with the help of some books, but the interesting part is openings were also a pretty big part of my wins. I know how to increase pressure when I have an advantage and have got to the point where I very rarely blunder if I have an advantage (If I'm under pressure, that's a completely different story). This is significant because the whole goal of the opening is to try to come out with a better position, at least when you're white. If I come out with an advantage and a grip on the position, I usually do very well.
I know a lot of opening theory and ideas well (at least the ones I play, though sometimes studying openings you even don't play is instructive) and because of this, the vast majority of the time I come out better, even with black if I'm playing something I know, and more importantly, I know why I'm better and how to exploit it. Openings have helped me understand strategy a lot better, and helps get me into positions that are favorable to me and have a decent idea of when to go for the kill and when I would be overextending and should delay it.
My tactics are solid, but definitley not overwhelming. I often win because of positional pressure combined with a careless blunder or one out of frustration, which is usually easy to refute.
Ironically I find that the endgame is on the bottom of my priorities to study. I used to hate endgames, even losing endgames one or two pawns up! Now I'm pretty decent at them, I know the basic technical positions and know the common ideas like "use your king", "opposite colored bishops are drawish", and "rooks belong behind passed pawns or 7th rank". I seem to get by at this stage because first of all I usually have a huge advantage by the time we get into an ending, so huge that little technique is even needed to finish it off, and second, the endgame seems to be either a big positional struggle (which I could use my understanding of the middlegame for, except that I should use my king also!) since kings can't be attacked, or a bunch of technical positions and pawn races. The latter is the harder part of course, but I usually don't get many close endgames.
I don't feel the need to get really good at them until I actually get punished for my mediocre endgame skill.