Ask HN: Help with programming language design and implementation.

I've implemented a very basic Lisp-y programming language, but there are some things which I'm not sure about how to fix/implement.

I'm happy with my parser, but the evaluation part is very buggy and in some cases unusable. I'd really like to end up with a usable programming language at the end but I've realised that I'm a bit out of my depth, both in debugging and implementing some features I'd like (continuations being a main example.)

Please recommend some sources for help in avoiding common pitfalls and implementing languages. (If anyone with experience wants to help me, also, that would be especially great.)