Eric Raymond is an excellent writer and you can't go wrong reading this article.
Also, learn how to do mathematical proofs. I don't know what the best way to do this is. I learned from 10th-grade Euclidean geometry class. Maybe you can pick up a good book on Euclidean geometry that has a lot of exercises in it.
Finally, pick up a good book on Lisp that has a lot of exercises in it and do all the exercises in it. Winston and Horn is good. "The Little Lisper" is also good.
Also, learn how to do mathematical proofs. I don't know what the best way to do this is. I learned from 10th-grade Euclidean geometry class. Maybe you can pick up a good book on Euclidean geometry that has a lot of exercises in it.
Finally, pick up a good book on Lisp that has a lot of exercises in it and do all the exercises in it. Winston and Horn is good. "The Little Lisper" is also good.