The problem is that most metronomes give you four clicks (one per each beat), and you don’t hear anything in between clicks.
To solve that issue you can use a drum machine which allows you to hear the clicks in between the beats. You can even assign a different channel for each step.
Here is the link to a free download.


http://www.d-lusion.com/DownloadDrumstation.html


It is important to warm up before you get into a serious speed training session, and after warming up, don’t spend too much time playing at slow tempos because it is unproductive; instead, find the tempo were you can still play accurately but is not too easy, and then practice a few times at your goal tempo, but don’t spend too much time there either, because you will develop some bad habits and poor technique, finally go back to the previous tempo and finish your session cooling off. In a short time you’ll notice your progress and it‘ll be time to set a new goal.
Hope that helps.