This guide will give a detailed opening, with pictures. There is not much I can do beyond that, because I don't know how your game will develop. However, I believe the opening I have created for you is the best, you can do. After the opening I will outline some advice, tips, and warnings.
Things You Will NeedYou will need to own the Diplomacy board game and have six friends to play with. Make sure you have separate rooms to discuss in. You will need pens, and paper as well to write orders on.
Step One: For the English opening goes as follows. Army: Liv - Yor. Fleet: Lon - Nth and Fleet: Edi - Nrg
Let me explain the opening for you. You will want to move your fleet into the North sea and the Norwegian sea, this is to make sure you get Norway in the Fall turn and so you can convoy your army in Yorkshire to Belgium. During the Spring negotiation phase you are going to want to talk to France and Germany and make sure that France is sending his forces to Spain and Portugal and that Germany will allow you to take Belgium in exchange for no interference over Denmark and Holland. This way you will get two neutral provinces, Germany will get two, as will France. Also, during this period of negotiations you will need to make sure that France does not send his fleet into the English channel. During the fall turn if France has moved his fleet into the English channel you can't convoy your army from Yorkshire to Belgium. You will need to support your army in Yorkshire to London, using the North Sea fleet. But, this is a small chance. Most likely France will send his fleet into the North Atlantic and move it to Spain or Portugal to get another territory.
Step Two: This step will have you continue your opening moves by capturing Norway and Belgium. Now, like I said in Step One: If France moves into the English channel you most abort. Read what I said on this matter at the end of Step One, because I detailed an effective counter-attack there. Step Two: Fleet Nrg- Nwy. Fleet Nth convoys Army Yorkshire to Belgium. You might ask why not just move the fleet to Belgium and leave the army in Yorkshire or London? Because, by having your fleet in the North Sea you maintain an important position in the North.
This was just a guide for the opening moves. It is impossible to write a play guide on any side for the whole game because as the Great Powers begin to place troops and fleets the dynamics of the board are going to change. You will have to be smart and cunning. You will come out of the opening turns with Norway and Belgium.
As the mid game begins you will want to maintain fleets in the Nth and Nrg sea. You will need to try and get fleets in the English channel if you can. Eventually you will have to choose to side with Germany or France. You will be a kingmaker. You are a lot harder to destroy than either Germany or France. England is one of the Wicked Witches, the second is the Ottoman Empire. You have a strong defensive position. It is very hard to take 18 supply centers as England, but it is very hard to destroy England. You will most likely survive the game. I recommend you side with France and defeat Germany. It makes more sense, with Germany defeated you have access to Denmark, Holland, Sweden, Kiev, Berlin, etc. And then you can continue to push west and take St. Peters. If you side with Germany then you will only have access to three ports on the northern Atlantic side. To get more ports you will have to go into the MED sea and attack Italy.
The most logical target is Germany. Work a deal out with France; side with him in exchange for the German Ports. The French player can take Munich in Germany and then Moscow, Warsaw, Sevestapol in Russia. As England you will want to take out Germany, side with France, and eventually take out Russia. Because Russia is in direct competition against you and Russia can make a deal with Germany and France just easily as you. The one thing you have that Russia doesn't is that he is going to be occupied in the South against the Ottomans and Austrians for a while. But, eventually a strong, centralized Russia could emerge as the biggest obstacle for England.
Tips & WarningsYou need to watch out for Russia. Like I outlined in the closing statements, if they emerge from the southern part of the map as victorious and consolidate their empire by building fleets and armies in the North you might be in trouble. However, this will take some time and Russia may lose in the South which would make your life a little easier.
You are going to need to choose a side between Germany and France. I recommend siding with France because it gives you access to more ports.
As an English player you are going to want to build Fleets, at least for most of the game. Your going to need to maintain control over the northern seas. Don't let other players into the NTH, NRG, or Channel. If you lose those positions you will most likely loose a supply center.
So, build fleets. Once you have all the ports you can take and want to move inland, trade a few of those fleets out in the fall reinforcement phase for an army.
Good luck and make sure you watch your back!