Indie Agencies, or Boutique Agencies, book your gigs. They generally get between 10% - 15% of your gross earnings. Many have agreements with Foreign/International Agents and split the commission with them, or, Artists may have several Agents in different territories.
Depending on revenue, most Agents earn a salary plus a portion of the commission they earned, the rest of the commission is pooled to pay for operations: Staff, Rent, Utilities, Telecommunications, Messengers, etc. Until they're on solid ground they're probably working for just a base salary, or a portion of their commission only. The Majors are expected to bring in 3x more than their annual salary.
Because of the different time zones, the Indie Agents can easily put in 10 hour days on a regular basis if they're on the East Coast - and that's just at the office, when they leave they're often at showcases sourcing out new talent. Each Agent signs their own clients and then becomes the Artist's Responsible Agent (RA.)
Because The Majors have bully clout they may be more appealing to the emerging Artist, but don't be fooled, the bigger the roster the more room to get lost. Bully Clout means an Agent can tell a buyer that if they don't book you, they won't get an A-lister, everybody's got competition, so this tactic always works - i.e., they can tell Live Nation that if they don't buy Emerging Artist's tour of America, they'll book A-Lister's World Tour with AEG. Bidding wars often ensue and well, that's one of the reasons your concert ticket is so expensive.
The Indie Agency doesn't have this clout so they have to work really hard to get you booked. They're in the business of developing your career, their goal is to grow you into A-list status. Sadly, once you reach A-list status, odds are you'll dump the Agent who shepherded your rise. You'll likely be lured by the predatory Majors who start sniffing around and promise you huge tours and lots of money if you sign with them. If you look at the rosters of Indie Agencies you won't find many A-Listers, but you can bet a lot of them started out there.
The Majors aren't interested in you unless you're already a bona fide success, or you're part of a package deal. The Indies take a chance on you and they work the phones tirelessly trying to get you booked. They also spend time with you and take on managerial duties.
When you're on a Major's Roster you're only as important as your last record. If your sales start slumping, so does your priority within the company. Also, the chances of you having competition within your agency are pretty great with The Majors. The Indies won't have several acts of the same genre.
The Indie Agent networks incessantly, of course the Artist has responsibilities too. It's not the Agent's job to sell your records, that's your label's job. It's also the Artist's job. All Artists have a responsibility to promote themselves as well - and it's much easier these days with social media.
You don't have to have a record deal to get an Agent, if you've generated enough buzz the Indie Agent can get you gigs that showcase your band, which could lead to a record deal. You don't have to have a Manager to have an Agent, when starting out that's 15-20% you save on commissions. (*in California only Agents are allowed to book gigs, Managers are forbidden to (http://www.boeschlawgroup.com/what-artists-and-talent-managers-should-know-about-californias-talent-agency-act-part-one-avoiding-disputes/)
Having the Major Agency's logo on your resume does open doors, I'm not going to lie, but, as I pointed out in 'The Majors" blog, they have financial quotas to meet each month/quarter, and that is their priority. The Band/Artist that makes them the most money is where their focus will be.
Artists helping Artists is a great way to help the Indie Agent grow your career. For example; gig swapping can expose both bands to a new audience, and touring together, where feasible, can do the same. The world really is big enough for the both of you.
The Indie Agent generally doesn't aspire to be a Major, it's too cut-throat and there's not as much quality time to spend with their Artists. Of course they want to thrive, the better they do, the more they can afford to keep discovering new talent. It's the circle of life.
You will find more Indie Agents at showcases or clubs with live music, they're hungrier. So, When your band is tight, and your interaction with each other and the audience is contagious, start sending Agents invites to your shows. Highlight your social media stats (if they're impressive.) Don't forget the music bloggers and other media reviewers. Be creative, be persistent, not to the point of obnoxious - just short of it, think good thoughts and if you've got what it takes, it'll take you where you want to go. I wish you nothing but success!