I want to start working on a remix for a contest, but I honestly don’t know what people look for in a remix anymore. How do you approach it? What differs a remix from a completely different tune with a shared sample? I mean Skrillex can remix “In for the Kill” and do nothing but reuse the acapella, and he still calls it a remix. Where are remixers left to go from there?
It can be a good idea to do a little research befor you start to produce. Usually it’s written at the remix contest what gender the remix should be in. If not you can check if the artist have got previous work remixed and check what style that is in. Or for an example if the winner track is going to be playlisted at at specified radiostation, you can listen to what type of muisc is played there.
When you have decided what gender the remix is going to be in, it’s up to you and your personal taste. A good place to start can be to just listen to the acapella and write a new chord progression or a base line that fits the vocals. Different chords can add a fresh vibe and make your remix stand out from the rest. Other things to consider is changing the bmp, adding instumental parts, chopping up vocals, sound design, make it sound up to date and so on. Adding some parts from the original track in another context can also work.
What’s importaint is that you are doing something that really sounds good to you, then it’s more likely that other people will like it to. Have no boundaries and be creative. If 200 remixes are submited for a contest you must think about how your mix can stand out from the rest and how it can grab the attension from judges and listeners.
Hope this can be helpful, good luck!
Do whatever you want, there are no rules. Although most contests usually seem to pick the most generic radio friendly remix possible, so keep that in mind.
comparing music with visual arts, i would say that abstraction is the key ingredient
that means preserving enough of the key attributes of something in order to keep it clearly recognisable still
while taking away or replacing blatantly all the rest 
if you succed to make it better than the original (at least for the target audience) you win
maybe that is it, the “genre” thing … when i think about it, the “best” (or most popular, that is) remixes have mostly been twists into a specific style !!
the more saddle-fast you are in your style and it’s root elements probably the better you acheive
I don’t know much about remixing, but I generally like when the remix turns the track into new direction, but still keeping the vibe of the original (kind of).
well put
like the epic 1999 - Funkstar De Luxe vs. Bob Marley - Sun Is Shining
haha, or 2011 teh Smoke out Dubstep Remix or whatever
but more typical have always been actual remixes of contemporary music into a contemporary “dance” version, like:
Xilent remix of Katy Perry Wide Awake
or back in 1996 Course ReadyOrNot of The Fugees 
i was fun back the because it was quiet unique
today there is probably a dubstep version for every lullaby
so, as esp81 said above: be creative !
Exactly! It seems that hosting Remix Contests is a way for an artist to raise their profile. You end up doing the promotion for your remix as well as 25,000 other people. Ergo all of your friends hear about this artists upcoming single/album/ep/fart
I did 3 remixes as of now. The first one was for open Matt Lange remix contest, the second time I remixed Crosses (just for my own fun), and the third one was for IDM musician who asked me to do it.
So, what can I say? 95% of open contests suggest you to remix some bland and generic EDM tune. They want you to create “the most radio friendly generic remix possible” indeed. You can check Soundcloud trending section and listen to some EDM remixes, you’ll get the idea pretty soon.
It’s more interesting when someone ask you personally to remix his tune, of course.
As others have noted, it really depends on the context. If you’re making something for a contest, it’s most important to just think about your target audience. I recommend that you don’t enter remix contests which are obviously looking for a style different from yours. Etymologically speaking, the term “remix” implies mixing the original elements in a different way. This is straightforward in terms of traditional recording, but in electronic music, the mix is the music, so you have endless possibilities.
I personally prefer remixes that are wildly different than the original track. However, I believe they should have more in common than just a vocal line. When I made Pistachio Island Remixes (shameless plug!!), my approach was usually to throw out all the pattern data and create new tracks from just the samples. This process resulted in tracks that often differed wildly in style from the originals, but I think they share a common feel with the original tracks, having been woven from the same cloth.
There are no limits to what constitutes a remix. If you find this lack of limits limiting, find freedom in your own limitations.
This is an excellent remix remix of rap song. Keeps the original vibe and the refreshing sound fits perfectly with the new beat.
I agree with agargara. When you do a remix, you should try to reinvent the original version of the song. It can be as simple as changing the instrumentation around the original vocal, or as complex as restructuring the vocal and making it part of the rhythm of the track.
I generally just try to add my own sound to the mixdown - sometimes it’s simple, but usually I go all-out and make an entirely new song. Usually I’ll load the stems into a horizontal DAW, like live, and chop them up into smaller pieces to load into renoise.
I’m really neurotic about drum sound - most people’s drums don’t make the cut, so i’ll generally use my own 
for the record, I hated remixing tunes, then my girlfriend (now wife 
suggested i do 30 remixes in 30 days - i did about 25 or so, and now it’s cake for me. definitely suggest that practice, and it’s easy in renoise - hell i’ve been making tunes in Live, and it’ll take me 3 days to make something that would take 3 hours in renoise… kind of a joke really — thus i’m back to renoise.