People talk on the forums all the time about sidechaining the 808 kick with the main short kick. But I will be honest with you, of all the trap records I've mixed, I've never done it. And that's a lot of records. I'm not saying it's a flawed technique - if it sounds good, it is good. But I will say that it is OFTEN (but not always) used as a shortcut that frequently leads to a comprimised sound. You've got all these internet beatmakers who don't know how to balance and how to EQ and how to compress very well. So they throw their hands up and just sidechain it. I strongly suggest you not use sidechaining as a crutch and just learn how to do things balance and EQ and compress. You will be FAR better off in the long run and the vast majority of the time your stuff will sound better. Save the sidechaining trick for the times when it's REALLY necessary.