The hardest part is getting yourself on the 'inside' of a handling agent or airline. A lot of dispatchers start off on check-in / the ramp then get internally demoted (

) to dispatcher if they wish. Depending on the handling agents or airline, you may also be able to go straight from the outside to dispatcher role with no prior experience. The handling agent / airline will provide all the training necessary so I wouldn't waste your time trying to gain extra qualifications to become a dispatcher.
I think it's pretty rare to see dispatch jobs advertised unless the company is desperate for them, as usually people from other areas within the company will internally apply for the jobs.
It's unlikely they'll be any jobs advertised until about Feb/Mar next year, when handling agents start their seasonal summer recruitment. If you did get a job on check-in/dispatch/ramp for the summer, it's usually an April - October temp contract but once you've got a foot inside, it makes it all a lot easier