Jazz Blues Funk Piano/Keyboard
There are many approaches to learning to play jazz and blues.
If you're a complete beginner you can start learning some basic jazz chords. You can use these to accompany your own right hand playing a melody or to accompany your own voice - or maybe other musicians.
To play jazz properly though, you need to understand the basic principles of harmony. If you've already learnt classical piano (up to about grade 5 ideally) then you already have some of the basic building blocks.
Improvisation is really what jazz and blues is all about but it's a bit of a mystery to many people - especially classically trained musicians, who've learned to follow the 'dots' - any straying from the dots is generally considered a mistake! Well, in the classical context, of course, it is. But straying from the original melody and harmony is exactly what jazz and blues musicians get exited about! The problem for beginners is knowing when to stray and, more importantly, where to stray.
Ultimately, really good improvisation does rely upon the inspiration of the moment. However, there are many useful guidelines and building blocks that can be used to help you on your way. Most improvisations are not entirely original, they are most often based on these guidelines and building blocks, which give you a good idea of the direction to go in (and, just as importantly, which direction to avoid!).
You'd be surprised how, with just a few fairly simple 'tools', you can create an improvisation that sounds pretty convincing. Once you start to get the 'feel' of improvising you'll find the inspiration will start to flow. However, you do need to take a few risks and 'go for it'. For those who have always played from the 'dots' it will require a leap of faith - but there's nothing quite like the buzz you get from just going with the flow and creating your own music.
Many of the great classical composers where also great improvisers - after all, improvising is really just instant composition! So, by learning to improvise, you are just following on in a great tradition.