The first thing that you need to do, in order for you to get any good at what Lewis Black does, is to carefully study and understand his art. You need to spend hours on end watching his performances, and if possible, you should also try and attend his shows that he does live.
This way, you will be able to develop and understanding for him and his art. This is the best way for you to be able to try and get close to being like him. If you fail to dedicate yourself to trying to understand how he does what he does, you might never be able to make humour out of anger.
Now once you have gone on to spend a fair amount of time trying to learn just how he does his routines and just how he throws his lines, the next thing for you to do is to go on and start to practice in front of a mirror. Start off small and keep going till you think you might finally be onto something. Once this happens, you can now take it up a notch by performing in front of a small crowd, before ultimately performing in front of a full sized audience. Remember to practice, since that is the only thing that will make you any good at what you do.
If possible, try and meet up with Lewis Black, since meeting him might result in him giving you some pointers and tips, which you can use to improve your performances even further in the future. Just remember to get as many tips from him as you can, since anything he tells you, could make or break your career.