Try to think what you have to do soon to excuse yourself so the other end wouldn't feel too bad when you need to hang up. Then if you can, or want to, express how you felt during the overall conversation. Did you feel happy? enlightened? This way the other end would know if it is ok to call again next time and what to talk about as well. Then you say pre-ending "take care" or "see you again" or "see you next time" then ending words "bye-bye" or "goodbye" or "bye" I usually say bye bye because I feel goodbye is forever.

well i always try to say the same sentence in my talking with friends to be known of it like sayin(it is the time) it means i gotta go but i think it is more polite to me i use it when iam talking face to face. but in phone i sometime say(i hope to meet u soon)

hmm... "Okay Bean take care have fun and dont do any thing i woudent do"

If you agreed on talking again later you can say: (I'm) Looking forward to talk to you again (/next tuesday). (Good)Bye. If you don't have a schedule, you simply say: See you (/Call you) again! If it's an interview, something that may have been inconvenient, or an unexpected call: Thank you for your time. If you know what your partner ist doing next, you may refer to it: Enjoy your holiday! Bye!

Your question is too simple, it depends on whats being siad in the moments before you want to end the conversation. However, in general I normally say "alright, talk to you later <term of endearment>, cya"