As a construction and engineering disputes lawyer, embarking on my own project and becoming an 'Employer' was probably more daunting then it is for most homeowners. The main reason for that is that I only ever see projects that are 'in distress'.
First we needed a contract, although I have seen some major schemes go ahead without one. The builder was pretty amenable to that (it certainly provides certainty for both) and we chose a simple standard form contract that dealt with all the important things like: start date, responsibility for insurance, scope of work and of course the price.
The most important thing for me was the price and having a contract that clearly states that there will be no increase to the agreed lump sum unless we agree and sign a costed variation is just as fundamental to me as it should be (but in practice often seems not to be) to any employer. It also means that I have had to spend a lot of time agonising over exactly how I want the build to look and what it should incorporate, so that there should be no surprises for either the builder or me. An architect once told me that once you are ready to commit, you are best leaving the builders to get on and build what you actually decided you wanted rather than changing your mind. Good advice that would save a lot of disputes, even if it does seem to be wholly contrary to human nature!
But then I have not stipulated a finish date or liquidated damages for delay. Why not? Because I don't need certainty as to the finish date. The works are the demolition of a conservatory and replacement with a traditionally constructed room. So at this time of year, I can't use it anyway.
I have agreed stage payment terms so if the work does grind to a halt, so do the builder's payments.
I probably did get more stressed then most would at such a modest project but I did approach it with the knowledge that the most important thing to record in the contract is what you actually want to happen and that extra thinking beforehand has so far led to a lot less stress during the build.