Seems to me that one possible sticking point to avoid is to make sure you have a way for all parties involved to agree as to when the work is complete. Many times failure to pay is caused by one party alleging something is not satisfactorily completed by the other party (at least to their expectation).
I've seen a 1% per month provision for late payments in a lot of agreements / contracts, but you may have to resort to filing a claim (civil suite) in order to obtain a judgement on this. It sounds good but I think it's rarely enforced.
Radar
