I’ve been doing a lot of little jobs since we moved into our new house. This experience causes me to want to write down the things I wish I had known this time two weeks ago.
The most important one is that if you want something to stay on the wall where you put it, use Rawl fixings to put it there. Many things come with fixings (plugs/screws) in the kit, and the best thing you can do with these is usually to throw them away; quite often the kit with fixings is cheaper than acquiring the other bits separately or they are not available separately. Happily Rawl sell useful mixed fixings boxes: I have the red/brown plugs-with-appropriate-screws box and the plasterboard box; both are excellent.
A close second is that a good drill is a worthwhile investment. I now have a Makita 8391DWPE cordless hammer/drill/drive unit which is many orders of magnitude better than the corded PowerBase one I was using before. The drill with 2 batteries and charger in a case was £100 (reduced from £170) and is the best power tool I have ever used. The most useful features are the keyless chuck and the variable torque-limit in drive mode which helps avoid over-tightening things. Most importantly it’s a good weight and well-balanced in the hand: the other cordless drills available in B&Q today seemed that they would be too heavy for extended use or felt back- or bottom-heavy.
If you’re laying cable neatly, assume you will need at least 4 times as much as if you weren’t doing it neatly. You also need a cable clip every 10cm on average. On either side of a change in direction for the cable you should use a pair of adjacent cable clips with the tacks on opposing sides of the cable; this stops either clip pivoting and keeps the straight cable runs straight.

+1 Makita – we have same one and it’s brilliant.