I've recently graduated high school, and I want to specialise in Bug Pokemon. I live in Johto, so I suppose the natural next step would be to talk to Bugsy, but I'm a bit lost on the process itself... Thank you for your help, you're a huge inspiration for me!
From what I’ve heard, Bugsy is very nice and approachable. You can stop by the Gym in Azalea Town and ask for special training, though e-mailing the Gym and making an appointment will definitely up your chances. I’m also a big fan of stopping by certified breeders to ask for tips on how to care for Bug Pokémon (though that tip might be a bit biased as I am a breeder myself).
There are so many books on how to care for Bug Pokémon, too! I love looking through books like that to see if I can pick up new strategies and advices.
If you ever visit Unova, make sure to visit Burgh in Castelia City. He’s a bit on the eccentric side but he’s a great Gym Leader who brings out the finest in Bug-Type Pokémon. I think Viola in the Kalos Region also offers training to budding Bug-Type specialists.
You have a mountain of options, the world is your Clamperl, so go out there and good luck!