well,

you COULD start with some epic sidechains ..
but i wouldnt..

just bc it has a reason: it takes allot power AWAY and id rather just want to have that power to blast me out of my shoes.

thats the only reason i dont use it.

you could just start with some kicks n cymbals to give you a beginning.
and build it with the rest of you cymbals / percs / thingy's.

let the bass come in at around 1 min ..
and let some melody flow into it at around 1:30 ??? just some random ideas ..

and when your done, try to build it .. off, the opposite of building-up, to make a breakdown happen.

Forgive me my Godd*amn english .. it sucks.

but i can atleast hope this wil kinda help you out :)
goodluck with it ^^

cheers.

Awesome Bro!

Now just make it into a song and I'll give you 10/10 :)