Another vote for Roger Musson's book. My first wheel built was a 700C rim onto an SP-PV8 dynohub and that lasted right until I had to replace the hub (worn bearings) after about 16,000km (road). The replacement dropped straight in and tensioned up in no time with the same rim and spokes and it's still strong.
One thing — buying branded spokes in the UK is an effing-expensive endeavour, for what they are. I've found it cheaper to get DT Swiss spokes from Rose Bikes in Germany, even with the whopping €7 shipping charge, compared to anything in the UK. Rose also does an adjustable nipple-spinning bit for a power driver (
https://www.rosebikes.com/article/cyclu ... aid:249279) — I DON'T use the drill with it, but just an extension rod and spin it with my fingers. YMMV.
Another thing — on dipping your nipples in lube, I don't go for this. I touch the tips of the spokes into a little chain oil, or 3-in-1, Musson-style — just a little, mind. You want the nipples to go on and to be lightly greased so that they can be adjusted after years of service. But lathering the nipples with lube is an invitation to them slackening off over bumps, as I experienced on the first fixed-gear rear wheel I built, which very nearly came totally apart on a hilly 200! A very wobbly final 50km to home and then I took it all apart, removed the excess lube and built it up again — it has been fine since (three years, 15,000km or so, possibly more). Too much lube and it also becomes easy to over-tension the spokes, such that they'll be impossible to undo once the wheels have had a couple of years' service.
A spoke tensiometer is a nice toy, but you don't actually need one. I built several sets of wheels before getting one and it didn't make enough of a difference to justify the £60-odd I paid.
I haven't gotten around to rebuilding my MTB wheels yet — at 21 years old, the (probably alu) nipples have seized solid, so I put up with the slight shimmy. I'll wait until I've worn the rims through.
