Breaking in after undergraduate: How?

Alot of the networking content on this site is focused on how undergrads can break in, and not so much on how a working professional (let's say 1-2 years out of school) can, which is a completely different game.

About myself, spent almost 2 years doing TS at a Big 4 then moving over to a Business Valuations/Corp Fin type of team (though not doing M&A myself). Arguably have a decent background but finding it hard to just apply online and get leads. I get some MMs HR replying back then setting up interviews, but once I pass that screen and get to the Associates/VPs they tend to sound un-interested in me, and I lose the chance. I think it's because they tend to already have a person they know who they'd prefer, whereas I'm a random online applicant.

People say networking but how? Is it still acceptable to cold e-mail professionals once you're a full-time professional yourself or is that reserved for college kids? I live in a non-finance heavy metro area so there aren't a lot of real life events I can attend either for networking. How is it done? Getting frustrated and feeling stuck in my current role..

Any input is appreciated, thanks.