How to make sure you show up prepared, and with all your gear.
It may seem as though it's obvious what to bring to a gig, but at least for your first few, it is a good idea to make a checklist of the things you will need, then to follow it as you load your car. The last thing you want to do is drive for a couple hours to a gig, only to discover you've forgotten something vital.
Note: I have been gigging for many years; I still have been known to pull over a few blocks from home to double check my equipment, convinced I've left something behind.
A good way to remember everything is to always keep it in the corner of a room or garage, away from everything else. If everything is gone when you are through loading, you must have everything. This of course will only work if you always put everything in the same place, put your instrument back when you are done practicing, and make sure everyone else in your household knows that these are your tools and they are never to move them. Also, you should establish a routine when you load things in your vehicle. Everything should have its place and order of loading. This way you are likely to notice if something is not there.
If this seems like an awful lot of trouble for a simple task, consider this: if you show up to a gig without all your stuff, in many cases you might as well have stayed home.
It is also a good idea to establish a routine for the day of the gig. Let's say you're playing Friday night at 9:30. You get off work at 5:00, it takes you a half hour to get home, so at 5:30, you pull into the driveway. You bring in your coffee cup etc. from the car, then immediately load up your gear. This way you don't get all sweaty in your gigging clothes before you even begin to play. (This is assuming you can garage your car, or live in an area where it is safe to leave your gear in the car in front of your house for a couple of hours at this time of the evening. If not, you may have to get sweaty in your gigging clothes after all).
Now, do all the other stuff you need to prepare for the gig. Even if you have plenty of time before you need to leave, do everything as soon as possible, and give yourself some time to relax before you go out the door. I know I need some time between work and a gig to relax and switch modes, and it is easier for me to do this if I know that all that remains for me to do is get in my car and go.
When leaving for the gig, always leave at a time that will give you plenty of time to get there at least an hour before the downbeat, if you have to set up. A half hour is usually sufficient if it is say, your second night at that venue, and you are already set up. For some people, even more time is desirable, depending on how complicated you setup is, or if you need to help with the PA, etc. Also, if you plan to stop on the way to a gig and grab a burger, leave yourself plenty of time to do that, as well. You may get to your favorite fast food joint, and discover that for no particular reason, the place is jam-packed. I would say leaving a half hour to forty minutes earlier for a "quick" stop would not be out of line at all. In my opinion, it is better to have dinner at home. Trying to eat while driving is a bad idea. You don't want to show up to the gig with secret sauce on your shirt.
By being there early, you get a chance to tune, make sure everything is working properly, and take steps to correct or bypass the problem if it isn't. If everything is working properly, you can sit and chat with your bandmates, or the customers, furthering your relaxed mood. You will make better music this way, rather than you would if feeling harried and on edge. If you leave late, drive to the gig too fast in your car, worried all the time about being late, or stopped for speeding, or worse, then show up, fly through the door, hurriedly set up your stuff, and make it just in time to start playing, this is, to say the least, not conducive to making good music, or having a good time doing it, at least for part or maybe even all of the first set. Also, what if after quickly setting up, you discover there is no sound coming out of your amp? Then the whole band starts late because of you. The club owner doesn't care that your gear isn't working properly or that it's "not your fault". He just wants the band to start on time.
The point is, if you show up early, and you discover the same problem, you have time to figure it out. No sound out of your amp is probably something silly, like a cord is not plugged in all the way, but if you are panicked and trying to locate the problem, it will be much harder to find.
Also, remember, showing up to a gig late, or unprepared, is one of the worst things you can do. Think of a band as a company that manufactures a product. In this case, the product, of course, is music. Now, with most manufacturing companies, if you show up late, it may make your boss mad, but it won't shut down the whole company. Your band, on the other hand, is completely shut down until you are on stage playing. You are an integral and absolutely necessary part of that band, and they can't do anything without you. So if you are not there, the whole "company" shuts down. Do this even once, and many people will look for ways to ensure this will never happen again. In most cases, the first step they will think of is replacing you.
No matter what, the show must go on, and it can't, if you are not there, or didn't bring all your stuff.