Ron, while I agree with about 98% of what Gary has said, there are two points I have a slight disagreement with.
As far as playing restaurants - not clubs, but DINING establishments, DEPENDING ON WHERE YOU LIVE, the hours may not be as long as they once were ... most restaurants around here - the greater Providence, Rhode Island area - that have live music start the musicians at around 6:30 - 7:00PM and they end about 10:30 - 11:00PM. Now the salary range is $150 to $200 per night, BUT, musicians who work these gigs are looking for the steadiness of the work, not necessarily the high hourly pay. Additionally, musicians who develop a following in one place can increase their salary via the 'tip jar'. Playing requests goes a long way here.
And when working in a nice restaurant you do not usually have the problem of dealing with people who ar drinking a lot, especially these days.
The secret to success with the above events is to go to the facilities, set up a meeting with the AD, and take a couple of calendars with you, one for them, and one for you. Some free pens go a long way, too. Now, sit down with them and book all your dates for the upcoming year - it's that easy.
Gary
I totally agree with Gary's approach, but get ready - IT AIN'T THAT EASY - especially for someone just trying to break in. What you are trying to compete with are the established players like Gary and Donny who have been doing it for years and get rehired because they are good at what they do and have a well earned reputation; and also with the 'youngbloods' who are really talented, are using NH/AL places to fill in for the gigs that might no longer exist in clubs or restaurants, and might often undercut price just to get some work. What I have found is that a lot of these young people often do not play an instrument at NH/AL places, even when they are capable of doing so. Many just sing with backing tracks, using a wireless mic to get 'into the audience' and 'shmooze' while they are entertaining.
I am pretty sure Donny would say something like "you have to give them something more", but even doing that - IT AIN'T EASY !
As for making $125 an hour on a NH/AL gig, I am pretty sure that is well above the average - but then Gary has been at this for a long time.
Gary's holiday list is a good idea, and you should keep in mind what holidays might be occurring around the date of your gigs, and perhaps have at least part of your song list dedicated to that holiday. Another thing I have done is GOOGLE songwriters born in a certain month and when I find a good one I will play a number of songs written by that person. It helps to developing musical 'themes' to work into your song list.
Along with restaurants and NH/AL places you might also contact country clubs for gigs at members' functions.
Getting music 'jobs' is no different than getting other types of work - you have to 'pound the pavement' and 'knock on doors'.
Hopefully, I have not dampened your spirit, but I just wanted to give you a bit of what I have faced, trying to get into this business at a more 'advanced age'.
Best of luck and much success.