Here's a chance to help your Dean out!

After an approximately one year absence, I returned to online Diplomacy at the end of the summer. Since then I have learned some things about my game and made a few observations about the game in general.

1. Although it can be difficult to determine when exactly each phase ends and the next begins, most games go through three phases: I will call them the opening, midgame, and endgame.
2. There are three skills that go into being good at this game: tactics, strategy, and negotiations. Strategy is looking at the map, comparing it to how you would like it to look, and figuring out a way to get there. Tactics and negotiations help accomplish your strategy. Tactics is the practice of using your units well. Negotiations is the practice of convincing others to use their units in a way that is to your benefit.
3. While all three skills are obviously necessary in all three phases, the opening tends to be negotiations-dominated, the midgame tends to be strategy-dominated, and the endgame tends to be tactics-dominated.
4. Looking back over my games, I find that I tend to do well in openings and endgames. I very rarely get attacked right away, and if I make it to the end-game, I can usually maximize my result (solo, smallest possible draw). However, I tend to lose my way in the midgame, which is when I tend to lose my way. I think this is because my negotiations and tactics are strong, but I have trouble applying them to a coherent, long-term strategy, especially in the middle of the game.

My question then is: how do you guys formulate strategy and then apply your tactics and negotiations to accomplishing it? More specifically, do you guys have any advice for a guy who does well at the beginning and ends of games but tends to fall apart in the middle phase? Feel free to discuss any of my above statements as well.