Ah, a fellow braless YLFer! I started going braless this past spring, mostly for health reasons. I have lots of health conditions, and I need my lymph to circulate well. It's hard for the lymph to circulate in the breasts when you are wearing a bra. I have found that my breasts have become firmer without the bra in the several months I have been doing this.
For me, the best way to avoid nipple poke is with a thicker cami. I have a couple of nude ones from Old Navy that work pretty well. Close-fitting tank tops also work well, as do silk undershirts (i.e., long johns). I also look for strategically placed pockets. I am also very picky about fabrics; if a fabric is very drapey, it can cling to the breasts and draw attention to nipple poke. I don't wear nipple covers because, to be quite honest, I find it demeaning to have to cover up with stickers a part of my natural female anatomy so I can be socially "acceptable." (Some women actually put band-aids over their nipples to prevent them from poking through the fabric.)
I have found that as the months go on, I am less concerned about nipple poke. If someone sees a nipple, good for them! Ha ha. Nipples are a natural part of women's (and men's!) bodies, and there really shouldn't be anything indecent in it. No one has ever said to me that they have noticed anything out of the ordinary, and I have never gotten a rude glance. I have sometimes caught people staring, but I think it is just because they are curious and don't see this every day.
There is a forum on the Internet that helps women go braless. You might get more tips there: Going Braless. The forum is dedicated to a lot of issues related to bralessness, some of which are beyond my interests (for example, there are parts on the forum dedicated to going topless), but you don't need to participate in those subforums that don't interest you. I have found it to be very helpful in gaining support for going against the grain.