For me, the best way to ensure I'll be able to hear OK is to try and control my environment as much as possible, and since I've been hard of hearing since childhood, I've had lots of practice doing that! (I formerly had serious loss in my left ear and mild loss in the right, and since the AN am deaf in what was formerly my "good" ear, making things that much more tricky...)
Like Arushi, in a one on one or small group situation, I try to get people to look at me so I can lip read, and in a lecture/theater type situation, I try to be seated as near the front as possible so I'll be able to see people's faces/mouths. If I can't be directly in front of the speaker, I try to make sure the off-center seating has them on my left (or "good") side.
When I go out with friends to a restaurant, they are all aware at this point that if I'm not sitting in the "right" spot at the table (ideally with them to my left and the bulk of the restaurant's noise on the right), I won't be able to follow the conversation. And I gravitate towards restaurants that aren't small and crowded--that's a sure recipe for chaotic, overwhelming noise.
I'm an expert on which movie theaters have the best acoustics and sound systems--it's really boring and frustrating to sit through 2 hours of something you were looking forward to seeing and then have no idea what's going on... (though by now I've of course developed my ability to creatively--and pretty accurately--fill in the "gaps" when I can hear at least 2/3 of dialog in a movie or show). And sitting slightly off center in the theater (so that my deaf right ear is closest to a wall and my hearing left ear picks up as much Dolby stereo sound as possible!) seems to help, too.
When I'm walking with someone, I gently coax them to walk on my "good" side. What's funny is that since my "good" side shifted after almost 10 years of marriage, for the first couple of years after my AN surgery, my husband kept getting confused about which side of me he needed to be on!
Parties are just plain tough. I try to find the quietest corner of the room and stick with the smallest conversational groups possible, but mostly, they're still...tough!