rewrite code for VBA excel

I want to rewrite existing code for vba so that it becomes faster. I wrote the code myself and I know it is too extensive and too long. This is just part of my program so after this project I have more but I want to take it in stages. I don't want it done on an hourly basis, I want a fixed price - I don't want to send excel sheets incl. explanation of how it works is too comprehensive