There's some really good advice here.
Some of the work is physical - but some of the work (for tournaments) is mental.
My advice is based on what I'm doing right now: Lots and lots of field work, from 180 feet in (that's 55 meters), shaping different shots with my primary approach disc (for me, that's the Prodigy P Model S). Throw flat, throw annys, throw stalls, throw hyzers, throw skips.
The purpose of this effort is focused on two outcomes: save strokes by being able to get up and down in 2 from inside 55 meters, and simplifying my bag - and decision making - by getting the most utility out of a single mold.
Yes, I'm working on my putting. But I'm also working on the shot that makes putting less of an issue. Have you noticed how well the pros make their putts? I want to do the same thing - even though my circle of 100% accuracy putting is considerably smaller. So I figure, why not practice on landing close enough to sink the putt?
And yes, I'll continue to carry other approach discs. But the disc I use most often (other than putting) is the approach disc. SO why not practice with it until I trust it for all sorts of lines, in various weather conditions?
Good luck!