I work with each one. Find the ones I can get a really good presentation for, and stick with those. Then I practice, practice and practice until I can do them flawlessly. Perform them, learn and re-evaluate. I have about six or so which I really know well. Their plots are also quite varied. Once you've got a good working set which you know like the back of your hand you can start experimenting with others.
Generally, when performing for friends who have seen my 'main ones' I just take various techniques I know and improvise. It usually works well.
So, in short - take your time. Choose a few which are quite different from one another, and work with them for a bit. There's no rush or hurry.
Hope that helps!

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