Reply to Transtion tips please...

Hi all,
I'm relatively new to DJin and pretty much self taught my self 'how to' by using youtube and reading community s etc..
I believe ive pretty much mastered 'the basics' ie 4 and 8 beat loops, cueing and dropping in the on the '1' count etc, but my mixes dont really sound as 'crisp' as id like?!
Im currently using Traktor Pro 2 (Awesome program) and a Numark Omni Control (seemed the better option considerin my budget at the time of purchase). I am just simply 'going from one song to the next' by beat matching and using the Bass kill switches to perform the transition.
It does produce an 'OK' mix but not as crisp and smooth as id like it.

Has anybody got any tips to assist in a smoother transition? Should i turn the bass knobs slowly the opposite ways or be using more than the bass? There are times when i can here what i can only describe as a 'popping' sound in the background, which is clearly the out track once the bass has been cut?! Sometimes however, the mix sounds absolutely awesome and as though done by a pro lol, hope you can what im getting at??

I am still learning and any advice would be appreciated!

Thanks for reading

DaveQ