Hi Xingnor!
Welcome! I have moved your question over the the "Collecting Help" forum. Let me try and answer your questions...
Firstly
What do all those acronyms that you use mean? RTS, SASE and all those.
You can find all the abbreviations here:
http://fanmail.biz/mboard/viewtopic.php?f=117&t=14169
Secondly
What's best? hand written letters or computer? (Guessing hand if a stranger can read it)
Personally, I like to hand write all my letters. I think it looks more personal, but that's just my opinion. Others type their letters. It's what ever you prefer. If you have "bad" handwriting, you may want to type. Some people even explain to the celeb the reason why they typed their letter is because of their handwriting.
Thirdly
Should i include pictures or other items, or should i let them find a picture or how does it work?
It's really up to you whether or not you want to send a photo. I have sent requests with photos and without photos and have gotten responses. However, some celebs don't sign unless you send a photo. In which case you can check the feedback history on this database for the person you want to send to and find out more info that way.
Finally
How should i write should i include personal story's (Not to long i guess)
Again, it's really up to you. I'd say try to make your letter no longer then one page (front and back). I usually tell the person why I like them, a little about myself and maybe a few questions I have for them. If they are on telelvision or in film, I include a story line that their character was involved in that I liked or a role that they played that inspired me.
As for tips, always include an self addressed stamped envelope, or international reply coupons and thank them for reading your letter.
Hope that helps!
Good luck!
~Annie