Improving at Software Design, recommendations.

I've been making larger and larger and more complicated Matlab programs and find myself refactoring more and more often. Are there any good books or other resources that can be recommended to help me design my programs better from the start and select the correct solutions as I go on. I've a fair amount of experience using Matlab and some in python and C++ however I'm entirely self taught, I'm aware of object oriented design patterns but am not sure to what extent they should be applied in Matlab. Can anyone recommend a course or book to help me improve my software design? Currently I do not have a good design process and instead just start programming and figure out problems as they turn up, this works but leads to messy hard to maintain code.

[per isakson]

BUMP

Not all design patterns are relevant in Matlab. See Design Patterns in Dynamic Programming by Peter Norvig

Much of what's true for designing programs in Python shoud be true for Matlab.