The current practice of many conservation citizen science organizations is to have a few training events and then basically let people motivate themselves to do the work. I respect that, but we all remark that on average it is not working or rather that interest and commitment are not growing fast enough.
The big conversation topic these days among citizen science organizations is about our struggle to attract and retain people.
For sure, it is hard to pin any reason in particular.
My feeling is that we would be better off if we invite people to be with us in the field. Making it an experience that we share.
But we should not stop there! We motivate people by being in the field with them as much as we can: it makes 'it' personal and it illustrates our genuineness and commitment first-hand.
I guess "it's lead by example", walking the talk, do the work, eventually, some might get inspired (depending on the person who's leading the work). Empower the people. Create doers if you can. Then, delegate when you get a doer who wants to commit. In all cases, be genuine and make sure that you empower, empower, and empower again all the time — all the way through.
The truth is that there are more followers than leaders. Another last truth is that there far too much distractions for people to keep the focus. It's ok, it's just the reality we have to work with. But we'll get there eventually...