I'm trying to create a menu system that I can run on an 89c420 using a 4 buttons and a 4x20 LCD display. I've tried several different incarnations and each time the code size just seems to be larger than it needs to be. I was wondering if there are any practices that are established for doing something like this. It seems like something I see used in a lot of areas and I was wondering if there are any established techniques that may make this a little easier to work with.

I am currently working with this in C but I am equally versed in 8051 assembly so suggestions that apply to either are welcome.