Performance review and optimisation

I am fairly new to Crocoblock (6 months or so) and have built a good demo site however I require an experienced eye for someone to look at my set-up and advise on any optimisation techniques or perform some enhancements to ensure that the site is robust and most efficient for when we launch in one month's time. I envisage a block of hours assigned to this task where we can quantitively measure improvements between now and afterwards in simple terms. Also any advice on common pre-live checks (or errors to avoid).