Your biggest expense as a function band is the cash you throw at rehearsal time. You’re likely to be doing covers, so learn the songs and your parts outside of the rehearsal room – get together with the other guitarist separately and work out who plays what when the meter’s not running. Discipline your rehearsal time at least to the extent where you have an objective.
Also, invite potential customers to see you rehearse – it saves having to play unprofitable public gigs, and the feeling of witnessing a ‘secret gig’ will often result in a booking anyway. Finally, don’t rehearse to the point where you’re sick of the sight of each other.
"Learn how to play quietly. Audiences at 50th wedding anniversaries and 60th birthdays often haven't been out to a gig for years and have forgotten how loud a band can be. Nan will complain and you'll be asked to turn down. It's easy to take for granted how much the chemistry of your band relies on the energy associated with volume. Rehearse quietly from time to time so if you do have to turn right down it will be less of a shock to the system." Chris Vinnicombe, Guitar Editor, MusicRadar.com