From experience....make sure that the controls that stop the motor are functioning. Trace the control wire/cables from the stop mechanism back to the motor and make sure you know how to operate them by hand. There is nothing worse than gettig a laid up motor running again only to realize you can't stop it!
Check and change all of the fluids and definitely change the impeller. If it is frozen and breaks apart on start up, pieces of it can get lodged in your raw water pipes. Also it is good practice to know where and how to access the impeller and how to remove/replace it.
Assuming your boat is on the hard at the moment, make sure you supply water to the intake while she runs and minimize the time you run the motor in gear as you can burn up your cutlass bearing.
Good luck and enjoy the project!!
p.s. - Nigel Calder's book is great. Don't get overwhelmed when you first look at it. The more you poke around your motor the more sense it makes!!