Learning a trade is learning a trade be it open Mike or Acoustic. Acoustically the artist has less to worry about, as a PA performance is a skill all on it's own.

Practice and making sure that you do not need a prompt so that you can then learn to take on board the reaction of your audience is a must for an Artist. Having the three cords written down on a crib sheet plus the words is not helping anyone improve. Not considering which songs you would most like to perform and going out to sing with a folder full of songs so that you can perform a different song after song each week is even worse. It will not soften the hearts of the performers who have spent the time to learn how to sing one of those songs without prompts. Other performers will be in your audience they may have spent weeks getting ready to sing that song out.

If you do get a paid gig from your performance on an open Mike night or and Unplugged Night first of all well done. You have a new set of skills to learn including singing songs that you are not keen on singing. You should also make sure that the fee that you are being paid is commercially realistic. That the gig has been properly promoted so you are not singing to an empty room and getting the blame. Try to be aware that the Landlord whilst having to make his or her living should not be ripping you or his customers off.

Doing a support for an established artist so that you have the same kind but changing Audience each night will help you polish your performance. No one should support Pay to Play. If you are supporting an artist with his own PA and or Sound Engineer make sure that you know enough about PA to make sure you get the sound that makes you sound at your best.

Better to get out there and enjoy your music and let others share in that enjoyment. Is worth far more that any money you will ever be paid so do have Fun! Just make sure you are not playing with yourself when you are on stage.