Sounds like you're on the right track (so to speak
A couple of tips that should help:
Copy the mp3 file so you have two files to work with ie. name them track 1 and track 2
For track 1 locate your cursor in the track just past where it ends and delete everything to the right of that point.
Zoom in around the end of the track to find and cut the end point more precisely
Use fade out over the last few seconds of the track
Save those changes to track 1
For track 2 locate your cursor in the track just before where it starts and delete everything to the left of that point.
Follow along the same line as above for the remain steps to create a good track 2
Hope that makes sense.