There are whole books which answers that question. The one I am aware of is pg's "On Lisp" which explains everything clearly without any "Haskellish or monadic

There are whole books which answers that question. The one I am aware of is pg's "On Lisp" which explains everything clearly without any "Haskellish or monadic mysticism". There is also the famous essay "Beating an average" and this very site as a walk of their talk. There are also SICP and PAIP and Norvig's Lisp Style Guide. Read the best thinkers.