Here are some tips on using MATLAB:

• Learn how to debug.
• Use vectorization functions like bsxfun, and allocate (in nontrivial cases) with repmat.
• Get the difference between matrix and pointwise operations, like / versus ./.
• Understand indexing, logical indexing in particular.
• Examine the differences in functions on reading (and writing) files, to get which function applies to your situation (compare for instance textscan with dlmread).
• Study passing function handles as arguments. Also, consider anonymous functions.
• Get the concept of precision and floating point comparison.
• Read the intro on graphics objects and their handles.

Knowing these concept and functions will help you to program more efficiently (and would also reduce the number of MATLAB questions significantly).