What are some tips for someone about to have general anaesthesia ?

Relax: It is safe. However anesthesia has risk and your anesthesiologist will go over them with you. But in this day and age anesthesia is very well tolerated provided it is being administered properly.

Preop gameplan: General anesthesia or regional anesthesthesia with sedation are both extremely safe when administered by a well trained board certified anesthesiologist. Please discuss all questions and concerns with your anesthesiologist prior to your surgery. Avoiding nausea, constipation, and inadequate pain control can usually be acheived. Safer monitoring and better drugs yield excellent outcomes.

Hydrate: I always suggest to my patients that they hydrate before an operation. I fell that this decreases their chance of nausea and vomiting after an anesthetic, as well as decrease their chances of major blood pressure swings. I would talk to your anesthesiologist and see if they have other suggestions to make your experience as good as possible.