Tools

You could build a project like this using just hand tools if you wanted, but power tools were a massive time saver. 

A decent cordless drill was the tool we used the most, not for drilling but for putting the frame together. We used 60mm timber screws, which have a star head instead of the usual Posidrive or Phillips, and they worked amazingly well. Also, lithium ion batteries rock. They weigh less than the old style NiCad ones and charge super quickly, so you don't have to down tools for the day because of a flat battery.

A circular saw was also essential for cutting sheet materials quickly, as well as for fiddly jobs like profiling the edges of windowsills.

A chop saw made cutting up the timber to make the frame very easy indeed. We actually got given this one, I'm assuming because its size makes storage somewhat challenging.

We also splashed out on a power planer, which turned out to be useful for skimming off wood round window frames, making wonky cuts straighter, and general bodging.