I would go in this webpage http://www.apronus.com/chess/wbeditor.php
Then plug in a position with you having 2 bishops or a bishop and a knight and just play against the computer. First of course look up how to actually do those mates on youtube or something. Then try it out against the computer.
I will admit the fact that I'm an intermediate player who doesn't know his basic mates. 2 bishops, 2 knights, and bishop and knight.
Now I've heard of Class A players not knowing their basic mates as well and it's a thing to procrasinate learning.
For one thing, it's not that fun. Second, these oppurtunities are next to impossible. Almost never is it that you'll end of with a mating oppurtunity like that. Heck I have only made it to a Rook vs King end game a couple of times only. So these are very rare so therefore, it's almost as if there's almost no need to study them.
However I do. And it's something everyone should know how to do at least by 1600.
The problem is that I'm having trouble learning them. The two bishop mate I understand a little bit. But I just can't do them. I always fail. How do I learn these?