Same rules as okcupid and shit senpai. Gotta be attractive. You get a huge bonus though because:
1) 99% of the dudes on the site are awkward as fuck. Just look at any cute girl's picture comments. Indian-tier cringe shit
2) The fact that you know English is obviously a huge boost and it makes getting replies way easier.

A lot of girls put "NOT LOOKING FOR RELATIONSHIP" etc. in their profile but that's to deter creepy fucking indian guys who want to jerk off on cam with them. Just ask if they're single early-on.

Flirting is a bit tougher because you can't be as subtle since most of the qts don't know English very well. You gotta be more direct than you usually would. It's fine because they expect it; the big stereotype about American dudes is how direct they are (Unless you're not American), so they usually love it.

So to sum up:
1. Get some mildly attractive photos. If you're 2/10 give up
2. Use the fact that you know English as a reason to message her. Unless they come off as super flirty, NEVER open a conversation with anything about how cute a girl is. Say shit like "I'm looking to meet new people, and I can help you out with English if you want."
3. Start flirting quickly, ask if she's single ASAP. Literally every cute girl I've talked to has been single, so it's more of a formality, but it says that you're interested. When you flirt, be direct. Innuendos literally mean nothing to them.
4. If a girl lives in some random country like Belarus that you'll obviously never visit, you probably don't need to waste your time unless she's super cute and super into you.

Bonus tip: Get kakaotalk. It's basically just asian kik. Getting photos is way easier once you're messaging on your phones