*clap clap clap*Basic Format
Let's start with the basic format of my translations:
At the beginning I put the important notes for the chapter, this usually is a notice to say what group the translation is reserved for or how you can use it if it isn't reserved.
After that the actual translation starts with the Series' name and chapter number, that is followed by the general chapter comments.
Next are each one of the pages, the pages are numbered in a "p#" format (# being the number) and are followed by the dialogs in that page, the pages are separated from each other with a blank line so that they're easier to tell apart.

Dialogs
I distinguish one dialog from another using a "Tag:" format, the "Tag" is usually the character's name (or a short nickname), gender/age (if it's a background character or a character whose name hasn't been mentioned), or occupation, they might be followed by complementary tags or I might use special tags, I'll talk about those later on.

Special Dialog Tags

• SFX
  I don't usually translate SFX, they're a pain in the ass to translate and most groups don't even typeset them, however there's two cases on which I do translate them:
  
  1. When they're inside a bubble. (Like the things in red here)
     
  2. When they're relevant for the story. (Like when one of the characters makes a comment on the SFX)
  
  
• Boxes
  I call a "Box" any dialog inside a rectangular bubble (as weird as that sounds XD), they are usually narration elements or thoughts but writing box is faster :P.
  
• "Text:" & "Big Text:"
  I usually only use this two tags for mangas that I used magazine raws for, they refer to the text usually present in the first and last pages of the chapter, if it's confusing I usually put where the text is located or the color it is with (for color pages) so that they're easier to spot.
  I only use "Big Text" when the text is like, really big.
  Example (green is "Text", purple is "Big Text")
  
• "Voice:" & "Thought:"
  This are the tags I sometimes use for generic dialogs I don't know who they belong too or that don't belong to an important character.
  "Voice" is usually a bubble that is just flying in the universe.
  "Thought" is what a not-really-important character thinks. (Check the "Thoughts" section in the Complementary Tags part for more info.)
  
• Object Tags (Arrow, Star, Asterisk, Heart, Magazine, PC, etc)
  I use this when the text is inside a representative figure (Heart, Book, Magazine, etc.) or are preceded by a figure (Star, Asterisk, Arrow, etc.).
  Examples: Star Screen
  

Complementary Tags

• sd
  The side dialogs, or as I like to abbreviate them "sd"s, these are little flying dialogs that aren't inside a bubble and that are usually handwritten.
  I use them like this "Character's sd:".
  Example (sd are in red.)
  
• cd
  Corner dialogs or "cd"s, they are the little flying dialogs that are usually handwritten and are located in one of the "corners" of a bubble.
  I use them like this "Character: dialog goes here (cd: corner dialog here)" or like this "Character: (cd: corner dialog) normal dialog".
  Example (cd is in red.)
  
• Thoughts
  This is for when an important character is thinking something (different to the "Thought" tag for background characters and this might be replaced by a "Box" tag depending on the shape of the bubble).
  I use them like this "Character(thinks): thought".
  This are examples of what I consider thoughts:
  Thoughts (Thoughts are in red, there's also the "cloud-like bubble" thoughts but I didn't find an example of that)
  
• "?"
  I use this after the character's name to indicate that I'm not sure if that's actually the character who said it.
  This might be replaced with a "Voice" tag depending on my mood (they basically represent the same situation).
  

Dialogs Split in Two or More Bubbles
You can refer to the first panel of the thoughts example to see what I mean.
I've seen some translators use a "//" to separate the text from each bubble, since I use the "//" for other things I just put this kind of dialogs as separate tags.
In the thought's example 1st panel the translation would say:
Suzuha(thinks): First part
Suzuha(thinks): Second part

Things between ()
So, I use "()" when there's a cd, but I also use them in other situations, this is mostly when the text includes an unicode character that I can't easily type (like music notes) or a drawing (like a character's face or an object).
If this were to happen the dialog would be something like "Character: Dialog (music note)", and you're supposed to replace the whole thing between "()" with the character/image that corresponds.

Text after //
Everything after a "//" in my translations is a comment, you could also call them translator notes, they're there to make you laugh or to explain things that can't be explicitly said in the translation.

Things Between {}
I use this usually when there's text on a screen or a book or when there's like panels inside dialogs.
They serve as indicators to where the Object/bubble starts/ends and they might have tags inside them.
An example of this would be the screen from the object tag example.
In this case I would do something like this:
Screen:{
Msg1:
Msg2:
Msg3:
//and so on...
}

Other Things
Special Pages
This are character introducion pages, index pages, special thanks pages, and story summary pages mostly.
I only translate them when I'm asked too and they usually have a special format unique to each of them, I try to make it as easy to figure out as possible though...

Well, that's about it, I commend you if you're reading this far XD, I'll be continuously editing this thing if other things pop out so check it whenever you don't understand something in my translations.

PS: Just if you were wondering, the manga I used for the examples are Shinmai Fukei Kiruko-san, Shokugeki no Souma, Koisome Momiji, Steins;Gate -Boukan no Rebellion-, and Hanamaru Youchien. They're all manga I translated and I like them all, give them a try if you can.