Also, to add, make it seem like we are actually reading a real diary from the perspective of your character. Put a date, and other things that would be in a dairy. Lay out the format and make the platform is just right so that when we read your dairy we can see the dates(base them off of the galactic calendar if you want to be more in line with Starwars).
Lastly be creative, use your imagination and write as you would if you were your character. Remember this is what they think, see, hear, and notice. Also add things from the forum RP that you are involved in or from in-game RP.
That is about all I can give you on the matter accept don't forget to name the title with your characters name. Say the diary of ______ is an example.