Hello all, I believe there are already guides on this, but I want to show you what i do, because 8 out of the 9 times i made a gm aplication i've been accepted.
Firstly, if your under 13 you shouldn't really apply, but there are the odd acceptions out there who make good developers and are very young. I once had a 12 year old who could actually compile his own mangos server, i was suprised If the server you want to apply for wants you to use the vent and you are young, you could try and get away with "I don't have a mic" but it may not always work. Always lie about your age if your under 15 i would say, unless you know the people don't mind. It gives you a lot higher chance.
Second, theres a lot of "persuasive speech tactics" you can use. I would use them personly, if you did not study them in school/you havn't studied them yet, then i'll list a couple. Get the person who's reading involved, make them like your aplication, just saying "you" a lot works. Give examples, use similies, metaphores, even listing at a part will make your aplication interesting.
Third, Never Ever make it short. If your aplication is short then i doubt you'll even get a chance on getting in. If they ask "List what you know about scripting", don't just say "i know LUA and C++", give examples, spell it right (Lua consider it a insult to say it lua or LUA aparently). Tell them how good you are at it, don't say "ok" give examples!
Fourth, It really doesn't matter how good you are at development. If your willing to learn and hard working, that alone will make you good. People don't always look for skills, they look for maturity and effert. If you want to apply for a certain server, get to know them first, play on the server for a couple of months and make friends with some of the gm's/admin's. You'll have a much higher chance of being picked then.
Fifth, If they ask which server's you've been on before, theres a bad opening. You could lie, name something random like "I played on Roarcraft but it closed down now"... 90% of the time they will think your lieing even if it's true, you have to either say, experimenting on localhost/none, or, name the pervious server, give them evidance, name the friends you had on there etc. They will look it up and find out you were telling the truth.
Sixth, slang makes you look so bad. Spell with proper English/American, do not say "wut" or "plz" etc. Just using correct punctuation gives you a much higher chance as you look mature and polite, if you start insulting people or "I know how to deal with retards" (excuse bad language) there not going to like it. Just doing it once could remove all chances that you have.
There are some servers out there though who prefer brief application, ask you a couple of questions etc, Common sense is involved a lot Do it how you think it will work out best!
It takes time for them to pick, if they don't reply in the first day It's normal. If they think you are good, they wont just make you a gm they will stalk you invisible (thats what they did to me a couple of times :yuck or something, trying to see if you are that good.
Stay active and keep to your word, don't let them down and be specific. Do not say something like "I know things." or "I know some commands" list them.
Here is an example of a ok aplication, although they could of been more detailed, instead of just saying check. Although it is humerous
If you follow all of these then you have a high chance of getting picked. I can not promise you, you will be picked, but you have a high chance.
If i missed anything please tell me,
I wish you like and bye bye,
-Salamanda aka stoneharry.