Book and prep in advance! I can't stress enough to get things done early. Also, when it comes to your makeup trial, we will look at any themes you might want to follow (dress colours, room colours etc), so if you haven't got any of those decided it won't help making the most of your trial.
Skincare, start any new skincare regime a good few months in advance (at least 3). This way if your skin is going to react to anything it has enough chance to calm down. Never do anything new close to your wedding day, not even a new eyebrow wax - make sure you've had it done before.