Ah, then you may not like my reply much which is - lots of pondering!
Basically, spend as much time there as you can now. Get a feel for the way the light falls on the interior, which way the prevailing wind blows, whether the house will fit the type of decor you currently like, or whether it might 'force' you to think differently.
In terms of the practical - spend money on professionals where serious skills are required (electrics/plumbing/damp/plastering type jobs) and save on ones that, while still time consuming for an amateur, aren't terribly difficult (basically the 'cosmetics' - getting a good finish when painting, fitting the kitchen, updating light sockets etc).
Also, when considering how much for professional vs DIY, remember to include the time cost.
When hiring builders, only hire those you are comfortable discussing possible issues with, or, more likely, comfortable asking questions of. As important is they have to be able to raise possible issues with what you're asking to be done - a 'yes man' is no use.
Never assume - even the best builder doesn't know what's in your head - write things down so everyone is clear on what's want.
Finally - have fun - it really is one of the best roller-coasters you'll ever go on!