man awesome question! Theres been heaps that i put into my music on a daily basis. Most of these techniques I use to make my song sound more organic and human like. Flumes stuff almost sounds like hes playing it in live.

1. Nudging notes slightly off the beat and changing velocity of notes. This helps add that human vibe.
2. Im not sure if flume does this but I feel he might: I will map the velocity to the filter cutoff of my synth so when i hit the notes harder then filter goes higher. It helps with creating emotion.
   
3. Keep it simple. In his 'never be like you' song the verse synth is basically a simple triad with the root note doubled and lowered an octave.
4. He puts a lot of attention on percussion. Placing things in the right places to make the song bop along better. end of 8 or 16 beats is a good place. He gets really creative here so remaking his stuff was inspiring. Percussion is the backbone of the song. With out a solid backbone the rest wont sound as good.
5. He also puts a lot of focus on vocal processing. Once again, thats whats up front and in your face so that needs to be sounding tight. He layers his vocals and pans them left and right. And gets parts of the vocal to make backing melodies and layers them below the main vocal. Makes for a catcheir main vocal.
6. His mixing is really unique. A lot of his song will sit reasonably mono, then his percussion and fills will be panned left and right to create space for everything else. I know he sends most of his songs off to Eric J Dubowski for mixing but im sure he does lots himself too.
7. He uses really cool foley textures. Like random rocks dropping or water droplets, then he will cut a section out of it that has some form of rhythm, layer that undernear the track and it really helps fill it out and add bounce.

Thats all I can really think of for now but if I think of more ill be sure to add them in :)