Guide by ASBusinessMagnet. You are welcome to share ideas and learn from the guide, but it's probably not a good idea to steal the guide and claim it as yours.
Preface
You may have many reasons to translate Homestuck. You may be doing it to introduce Homestuck to your non-English-speaking audience, or to simply practice your translation skills. That is irrelevant. The point is that you want to translate Homestuck, and that you may not be aware of every single tidbit of the experience.
To begin with, Homestuck has two major problems that make many of its translations (that I begrudginly have to list, unless it's johnnotegbert of course) unsuccessful:
a) It is long. http://readmspa.org/stats/ tells me it's currently at more than 700,000 words, and that is a bitch to read, let alone to translate. Luckily, there are alternatives like the other MSPA adventures, so if you want to simply practice your translation skills, those are a better option.
b) It is difficult to translate. Homestuck loves to engage in massive wordplay, including fish puns, horse puns and a few different kinds of puns that it invented solely for the purpose of a few characters. Once again, it is more of a problem with Homestuck, rather than a problem with MSPA in general.
But let's say that you have looked at these and still want to translate Homestuck (and/or any other MSPA; maybe even all of them). What will you need to consider?
Translating alone/with a team
If you have located another group of Homestucks that speak both English and your language, it might be a good idea to translate Homestuck as a team, rather than all alone, but both variants are acceptable, because both have their own problems:
When translating alone, you consistently have to find motivation (you can't translate 700,000 words in a weekend all alone, no matter how hard you try), but if you're translating in a team, unless each one of you is taking different jobs (one is translating the text, the other is translating the images etc.), you'll need to ensure consistency across all of the translation (to see what I mean, head to the Italian translation thread).
Hosting
Right now, just looking at this website's homepage, I see three major options that people use: a) coding their own website, b) using the MSPFanVentures website, or c) using a third-party blogging website.
Unfortunately, the first option requires you to be programming-savvy and know about such things as SQL tables and I can't speak with experience about LiveJournal or Tumblr or whatever editing, so I can only help you with the second option, which has its own separate page: So you want to translate Homestuck?/Using the MSPFanVentures website
Planning
There has been planning undergoing Homestuck, and there is going to be planning undergoing your translation.
One of the first things to consider is the character nicknames (chumhandles and/or trolltags). They all actually follow this pattern, in which their words begin with the letters A, C, G and T (based on the four bases of the DNA blah blah blah). Therefore, when translating them, you'll probably need to take this into account. (Perhaps the language you're translating to doesn't use the Latin alphabet, and as such this can't transfer. Perhaps you think it's a better idea to keep the chumhandles/trolltags as-is. There are many options here.)
As well as that, the game-like elements, like the Sylladex, the strife mechanics etc. all have been thought out and have these complicated roots, which your translation aid might not cover. It is important to have their translations thought out, and to keep them consistent throughout the adventure.
Puns
Thematic puns, like the aforementioned fish puns and horse puns, are a thematic of Homestuck, and have been the number one comment on why Homestuck is hard to translate. But luckily, there is something to consider:
They don't affect words or sentences; instead, they affect characters. So if you can't use a fish pun in one place, use a pun in another place where the same character speaks.
Translating text
This one's probably going to apply to any translated work, not just MSPA, but just to say it: your translation needs to flow like a native-written text. Word-for-word translations tend to be broken and jarring, and it is important to know how to translate.
Translating images
Here's where things get a bit difficult. You'll need to have a good image editing tool (like Photoshop or GIMP) and awareness of what fonts are used where in Homestuck. Ultimately, though, these are the same as translating text (except this time you get to deal with text in different styles, like the old-timey style of Colonel Sassacre, the ornery style of the Data Structures book, the incomprehensibly rad style of GameBro etc.)
However, this is not nearly as difficult as...
Translating Flash files
Most Flash files are actually linear animations that can easily be decompiled, parsed into Adobe Flash and edited, but walkarounds involving ActionScript have been known to fail with many people. If all else fails, you can simply find a transcript of a game and translate it, and when you submit the page, link to that translation of a transcript.
There is a second method to get the walkarounds to work.
You can download an open source command line tool named swfmill here: http://swfmill.org/ It can be used to transform the whole swf file into one huge xml file. This xml file contains all the actionscript data, this means all the dialog text, too. You can translate the dialog strings and then compile it back into a swf file. You should open the xml file with a suitable raw text editor, like Notepad++. Windows Notepad can't handle some newline characters, and Word is unsuitable for so much text.
Copy the swfmill.exe in the same folder as the swf file.
Now open the windows command line (start menu - run - cmd.exe, right click and run as administrator, if necessary). Commands to use:
- Convert flash to text: swfmill swf2xml flash.swf raw.xml
- Convert text back to flash: swfmill xml2swf raw.xml flashTranslated.swf
All text is mixed with variable names, so be careful when translation single words, they could be variable names!
Translating HTML5 games
At this point, I can't even begin speaking of what is involved with the translation of those things, and as such the previous advice as with Flash files applies. (Though, I hear these are open-source, as per the design, so their translation might actually be easier, rather than harder.)
Community
Okay, so let's skip ahead a bit. By whatever means, you now have translated a considerable part of Homestuck and are now looking for people to talk about it with. Unfortunately, you'll face the same problems English-speaking Homestuck fans face:
a) Homestuck is controversial.
It openly features gay, lesbian and those kinds of characters, which more conservative communities might not take well, and there are plenty of homophobic people in the world that may not take Homestuck well.
And if you are looking for people among English-speaking websites such as Tumblr, they are probably going to take the whole "reading it in my own native language" thing negatively, because the original is superior in every way to a translation etc.
b) Homestuck takes off slowly and gains momentum later.
Many people, based on Act 1, claim that Homestuck is simply not interesting, and if your translation hasn't gotten to Act 2 yet, this is going to cause additional problems.
More points to be added later...