12+ years of gigging with original bands; it can all be summed up in few but long points;
members that want band to get big must be aware that band comes first, everything else comes second. Working ethics is a must, regular rehearsals are no1. Set goals. Now, goal is not "let's gig", gigs are at first just tools to get bend exposure, so is internet etc. It's sometimes smarter to spend a year rehearsing regularly then just play gigs for the sake of gigs. Don't hit the stage until band is a uniform living, breathing tight machine. And that takes time, patience and dedication. With policy as rigid as this, you'll easily eliminate weak links in the band, and by that i mean members who aren't really into working hard. You see the problem is that many of us try to avoid conflicts and give to much to people who use us. So problem is that sometimes band members are not so into firing that member (members) that don't do their job, won't practice, are bad and hold the band down. Usual excuse is "oh, no if we fire her/him, how are we going to find another drummer/guitarist/key/voc..etc", but reality is that band suffers more with members that are holding it down and are unproductive links in a chain. It's better to have 2 man band that works hard (even if it's something ridiculous like heavy metal band that only has drummer and vocals) and practices and is out on a hunt for serious members than having a band that has slackers. seroiusly, you can practice today without "important" instruments. heck, have someone make tracks/type them on something like guitar pro, and reharse with the rest of the band to it. it's simple, it's easy and there is NO excuse for not working. If you are the only band member that wants to work, fire everyone, practice at home, write your music, and look for better members. EVERYONE IS REPLACEABLE -> work and friendship should be like church and state - SEPARATED.
You need a product. Products are in first place songs and then shows and to some extent story and image. To get all of that you need a product -> songs (music). Creativity comes from playing and working. Shift reh. spaces, try different instruments, gear, listen to a bunch of different music, but never stop playing cos you don't have inspiration. You create by playing. Now, to get all of that you need to play a lot with your band. So you should really dedicate yourself (and rest of the members also) to rehearsing a lot. AND REGULARLY. For me it's about minimum 4 rehearsals a week + 1hour at least of home practicing every day. Polish those songs, you should know every single note from first to last beat, and you should know to play every song perfectly. That is VERY important. Point is, if band plays songs really well it can translate it's music better to audience and can also focus on many other things during a gig like communication with the audience, making a real show and not looking like a bunch of statues onstage. Know songs perfectly and stage fright will be gone more or less.
Record everything. Every rehearsal, every gig. Listen to it, try to find what sounds off, where are the mistakes and what translates to audible songs and what is gibberish. what is fluid and what sounds crappy. Analyse, think, be critical. go through every detail with band members, point out everything and be open. try to fix issues with work, tasks and goals. "this sounds off, let's try it like this" ... "you are having trouble with this part, let's rehearse it a few more times and then see how it sounds." ... "this part sounds too hard, we all need to practice it at home better, everybody, practice this at home and be ready for the next rehearsal"
Also, it is really important to have all of the band's songs written down, notes or tabs, doesn't matter, whatever members can read. Spread it out on a drawing board when rehearsing. That way everyone know what she/he needs to play and what others are playing. Productivity will go off the charts. If someone slacks, either warn them or if they ignore that, fire them. zero tolerance for ********. replacement will come if the band is working hard.
Good thing that i found out is making the drummer use a metronome on rehearsals AT LEAST. That makes the band play tighter, clears up the sound and really shows you where the problems in performance of the members are. It's a miracle tool, really. If drummer refuses for stupid reasons like "metronome sucks out the soul of the song, great dummers don't use them", just know that drummers can be replaced very easily. rythm machines, typed tracks etc. how hard is it to type in drums and play them on cellphone?

But before taking extreme measures, small issues can be resolved empirically. Try this, ask him/her to record one song on rehearsal with metronome and the same one without. Thing is that bad drummers hate metronome cos it is distracting to those who don't listen to song, just listen to themselves when playing. That's the worst thing musician can do, and that's what bad drummers (and other bad musicans) do all the time. Rhythm is as important as intonation.
Now that we got that, it's time to get the other part - marketing
Thing is that today you have all these amazing tools at your hands, it's a musicians paradise. Youtube, facebook, soundcloud etc etc. Question is how to use them to promote your band. There are many answers to that questions here and in may social marketing books and guides, that can be really useful. So i'll just point out a few concrete things and ideas you can't find in those;
- expand your base by preparing audience before gigs; try to get to talk to venue's DJ's (if it's a club, bar etc) few weeks /days before playing there, give them your songs, ask them if they could play your stuff from time to time, that's really great to get audience to get a tiny bit familiar with your songs.
-hand out promo material before/during/after gigs - get creative, reward those front row dancers/moshers/lighter holders, try something cool, get ideas, just don't make it blank
-get someone to take pics of your show, entry level DSLR cameras cost pennies today and there are gazillion of wananbe photographers that would like to take pics of you. pick out the best. Get those photos on your band's facebook page ASAP, make audience find you on facebook and tag themselves, reward them. example, "find us on FB, see the pics, tag yourself and we will pick a lucky person who has tagged her/himself and send ..... promo/merch/CD...". that will expand your reach. Get a list, write down those rewarded fans on it and next time you gig at the same place, contact them, get them a free pass, and stick it on their facebook wall. They will get free stuff, and you will get instant promotion machine.
-get to know the audience after gig, shake hands, smile, get to know them, don't ask how did they like you, thank them for being there, hand out promo, smile, be thankful, approachable and nice.
-FB/youtube/socialnetworks need material, give it to them. Make videos, reviews of your gear, writing process, rehearsals, whatever.
-Develop an image. example when someone says Iron Maiden, you think of eddie, steve harris's galloping bass, melodic fills. They found out what was unique in their band and then thy started to build on that. Image should not be just made up, it should be a highlight of things that make your band unique, build it on that. Your music and playing should be the foundation on which you build your band's image.
- Don't settle for ****** gigs, if something looks bad, avoid it but keep in mind that sometimes good promotion and reaching audience beats money in the early stages of the band's life.
-If things go bad , keep a positive attitude, and remeber, it's not talented that make, it's persistent that make it big. Talent means s*** without work and not giving up. Show turns to train wreck, smile, play and do your best to get through.
Remember that even if you, your band and your family and firends think your band sounds good that it does not mean that it really is good. Don't settle for good enough, strive for best.
You follow these points, you'll have better chance. Thing is that's not the easy way. It's hardest way but it's the right way. Things don't come easy, you gootta work work work and sometimes all of that work can seem like it was all for nothing, but if you bite it hard and work your way, all of that work will be rewarded sooner or latter.
feel free to correct me if i'm wrong. i would appreciate that