The Institute of Advanced Motorists is the UK's leading road safety charity and has over 100,000 active members, all of whom have passed the advanced driving test on a motorcycle or in a car. There are benefits to IAM membership such as better insurance terms, discounts on this and that, and so on but the real major benefit is that the "conversion" to advanced driver means that you will be one of the safest drivers on the road.
I don't mean this in a pompous or snobby way - I mean that you will genuinely be riding or driving in a way that is safer and more comfortable for you, for your passengers and for everyone else on the road. I had been driving for 30 years when I took the IAM course, it opened my eyes.
IAM coaching concerns itself with three things: improving your skills, improving your observation and making you drive systematically. The "system" is the same one used by the police and other emergency service drivers. Even if you already consider yourself to be a competent driver/rider I highly recommend having at least one session with an IAM Observer.
I was coached by Thames Vale Advanced Motorcyclists (TVAM), the largest IAM group in the country. If you ride a motorcycle then take yourself up to St Crispins School, Wokingham on the 3rd Sunday of each month at 9am the next being 18th March. You don't need an invitation, just take yourself and your bike.