The absolute, number-one, most important thing to remember when playing live music in front of an audience is this:
The very best way to get more people to repeatedly come out and see your band play live is word of mouth. When your live shows are great, people will like it and talk about you to their friends both online and offline. Besides the obvious point of playing good music that people like, there are 5 main areas of preparing for your gigs.
1. Your individual playing
The most important thing you can do (individually) to prepare for your gigs is to focus on playing your songs 'consistently well'. To improve this, practice your songs in a wider variety of environments and situations. Play your songs standing, walking, in the dark, under a strobe light (if you have one), while talking, without looking at your guitar, while friends are listening, etc. The key point is to practice playing consistently well in all those different scenarios. This will help your individual performances on the stage.
2. Your band's performance
When your band rehearses, you should NOT be focused on playing the songs correctly. If your band mates cannot play the songs flawlessly BEFORE the band rehearses, send him/her home to learn the songs. Once he/she has truly done that, then bring that person back to band rehearsals. Band practice is not about 'holding people's hand through the process of learning the songs which should have been learned at home. If you have a band mate who needs your help learning the songs, you can do this by meeting alone with that person to help. However, if this is a consistent problem, then you may need to replace that band member for someone who is better (or less lazy if that is the case).
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