Ok, i actually get a load of demo submissions, i eventually listen through them all, bearing in mind this is a free netlabel - as is my time given - i have to work all that round my life
What this means is that you'll need some patience when submitting a demo (this is true of any label btw).
It really really helps to include a bunch of info about you and the music you're submitting to grab attention - tell us about your music, which track is your favourite you submitted and why etc etc, we don't want your life story though, just what's relevant. there's a significant amount of tracks sent that are just "hey bro, check out my soundz and you can release them on ur label" then i go to find that such submissions are already listened to and downloaded by a load of people already. these are the demos i jst put to one side and listen to if i ever have time (when i'm realy bored) - which is usually never tbh. There's not enough time in the world to go through every demo submission so you really need to make the effort to stand out - in this case just follow the guidelines in the OP. simple.
Pro tip for any one sending anything to a label, if you really are keen to see your music on that label you submit to, make a SERIOUS EFFORT to read all the submission guidelines, twice, then twice again. then double check everything before you hit that send button too. then only when you're sur hit send. then if youve heard nothing back in approx 2 weeks, send another email as a friendly "nudge" about your demo.
Ultimately, any label wants to have artists that are keen to be on that label, not just looking for any label to release their music and this comes across in how you go about submitting your demo.
One last point - IDMfNetlabel doesn't really look for individual tracks, so sending one alone in the hope of getting that signed is generally a waste of your time and space in our email inbox. Even if you'd like to submit music with a view to releasing something you're still working on, send a 3-4 tracks so it's easy to gauge your stye and abilities.
And you know what? if your English is not great or not your first language, then try to get help from a friend whose language skills are better than yours, it just helps in the long run to make it as easy as possible to listen to your demo and know all about it.
so to sum up what's true for almost every label - The easier you make things for the label people, the easier it is to get signed