It depends on what you want out of them. A date? A friend? If I just plan to be friends I usually dont tell them I'm BP, this and that, etc until the topic comes up on its own, or until I do something weird. If i want to date them i tell them sooner. Theres not really a smooth way to tell someone things like this, so i just up and tell them. Ive had a lot of different reactions, but the people that would have worked out in the long run always accept it and move on. It weeds out people pretty quick.
I have no idea how my current relationship is working. My girlfriend is insanely tolerant of all my ****. If i do something way out of bounds I do my best to apologize.