Narrowing the focus down to some simple mechanics, you don't need to mail control everytime you want to blow your nose, or, for instance to negotiate with someone, but you will need to gain permission before launching some kind of action, particularly where this concerns another player. When your character does something, or wants something known, don't neglect to inform relevant parties - especially the news services which are the primary brokers of knowledge in this type of situation. Co-operation with other players is also effective as you will have support for your version of events, as well as making your plan appear more feasable to control. As with anything in life, you draw from the sim what you are willing to put into it, and players that really make an effort not only have a lot of fun, they learn more about the Middle East, and about diplomacy in general, then they could ever hope to do from a textbook - because you have a chance to put into practice what you are supposedly learning. The structure of the simulation is quite loose, and you are pretty much free to decide what your character will do - commonsense should decide limits with the odd letter to control for permission.
Control is also at hand to answer any queries and generally give advice.
The messages themselves can vary in content as you like, but try to make them worth reading, pay attention to spelling and presentation. The Sim vs Reality Confusion on this topic has been known to create problems in past sims. Basically, you must remember that the sim takes place in its own little world, removed from the real world. You will be simulating Middle East political happenings, not simply regurgitating them from what you see on TV or in the paper every morning. So, by all means look to the real world for ideas on what to do, but if a bomb blows up in Algeria in real life, it doesn't necessarily have to take place in the sim, it can, but only if you make it happen - by checking to see if it's apprpriate and asking control for permission.