What I would advice would be to use a mixing software like Native Instruments - Traktor for mixing tracks together.
If you prefer non-live mixing you should definitely learn how to use a software like Ableton - Live.
Your setup may vary depending on your needs, but one important thing in a live mix is not recording an audio feedback from your microphone.
I recommend Ableton - Session View. You can drag each clip onto a track and set the global BPM (the clips will automatically fall into time with each other) - then draw in the fades and such.
There are several algorithms to choose from to make the time adjustment sound more natural. I prefer to leave it on beats > transient.
This is all super easy if the ...
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