I like helping out a fellow DJ!!
One thing you should be careful about is your volume levels. You had the tracks at a good volume and then one track sounded "empty". It was alot lower than your other tracks. If your mixer has a level meter, make sure the volumes are close, but not to the point of distortion.
Wait for the breakdown of a track to mix, especially if it is a house/techno beat. Hip hop you wait for the chorus.
I myself like adding intros to tracks that dont have their own. Whether thats a 8 bar or 16 bar intro. I have some programs I can let you have that help make your own intros and are easy to use.
Good work though!!