Since I missed last turn I figured I should try to get this one right away:
France: You have really maneuvered yourself out of position, really for three moves in a row. Way back in Autumn 1902, your move to Spain already had begun to move your units out of position. Your acquisition of Belgium slightly offset that, but then you kept doing it. As you have now seen, the convoy into Tunis was simply a bad decision, as it essentially guaranteed you could never get any more centers from Italy, but that isn't all it did. It also left you wide open on the continent, and you exacerbated the problem this past turn by moving your army in Burgundy to Gascony (really Spain should have gone to Gascony to then Burgundy should have at least stayed where it was, and probably stayed in Belgium, but that second statement is perhaps a little easier to say after the fact). Stab prevention is 90% deterrence. If you just had a few armies making it clear that you would be hard to take, you would likely not have been stabbed.
The good news is that, as France, you have a naturally strong defensive position. If you can get Italy back on your side, you will be in ok position. The key is figuring out how to get your army in Spain "unblocked" by Gascony and back in play. If your units were in position, you would be nearly impenetrable.
England: First, a quick tactical note: Position is much more important than supply centers, especially when you are making a stab. Since you have no armies near France, you are in for more of a slog than was necessary. It would have been a much stronger move to convoy Norway to Belgium. Now you have to choose between supporting yourself to MAO and convoying an army into France, and that is a serious bummer. It is the difference between having a guaranteed center in France this coming year with a coin flip for a second and only having a 50/50 chance of getting a center at all.
Having said that, I like that you made a move on someone, but the key will be to think ahead more than the one or two centers you have on the horizon. You have Moscow, which is usually one of the two choices for an 18th center for England (The other 17 being all the ones on the line from St. Petersburg through Marseilles or above), so if I were you, I would be thinking about how I could solo. The good news is that Germany has only one fleet. You should try to keep it that way. At the same time, if you do want to solo, you can't do it with only fleets (you can't even take out France effectively with just fleets).
Second, the trick to solo, like I said in my first post, is to time other people's crises to line up with your goals. With Russia and Austria gone, you are quickly running out of people to make your pawns. I don't want to say too much here, but I encourage you to talk to your TA about how to position yourself for a solo attempt.
Note to the other players: England isn't even close to soloing yet. Please don't let my above commentary cause you to overreact. There is no need to worry. Italy and Turkey have equally good chances to solo, and Germany still can as well.
Germany: England moving on France was great great great for you. I think had France made slightly stronger tactical choices you may have been in trouble. Having said that, you aren't out of the woods just yet. While it is certainly not a strict rule, in general all powers should be trying to find a corner so that they can minimize their fronts. You don't have that yet. The good news is that you have some diplomatic currency now. England is fairly committed against France, so you should be able to have your way with your negotiations with both powers. Don't be afraid to take advantage. Now is not the time to be overly nice.
Italy: Great job getting Turkey on your side, and England's move on France can only be good news for you (although it may have been better for you if it actually came a turn later). However, you aren't quite out of the woods yet. I'm not privy to the communication of course, but you need to get a sense of how much your alliance with Turkey was a response to the now-crumbling Western Triple, and how much it was a true alliance that will last. The best time to be in a slightly awkward position, though, is during builds, so in that sense you are in great shape. The reason I say that is usually even if people plan to stab you, you can make them make builds that you want because they want to postpone the "big reveal" until a spring move when they are moving all of their units. Keeping that in mind, you want Turkey building an army.
The best thing (and the worst thing) about playing Italy is that you get to (have to) shape the game to succeed. At the risk of sounding like a broken record, it is incredibly important you think about timing: How fast you want France to fall (or if you want them to fall at all), why and how you can help Turkey get further in the game (or not), how much pressure you want Germany feeling, and so on. If I could choose to jump into this game as any power, I would want to be you, but more because I think it is the most fun position than the best, per se.
Turkey: You are in a great position, but you face the perennial problem of a 7-center Turkey: What next? Like England, you should be thinking about how to set up a solo attempt. But unlike England, you are nowhere near crossing the stalemate line yet. You need to think about how you could make that happen. Usually for Turkey their 18th is either Munich of one of Marseilles and Spain. But you aren't in position to just go get those centers, you need to set up the diplomatic situation so that you can. I don't really feel like I should say more than that. Talk to your TA.
Russia: NMRing for the loss? That's too bad. I think you may have been able to get Turkey to leave you Rumania had you tried.