Creativity is the name of the game today. If you want to stand out, give people something to talk about AS WELL as the music. Package it nicely, and you can sell more copies. Maybe you don't have a sweet deal with Samsung's S4 release, but don't worry. There's still lots of opportunity for you out there.
First, lets cover the basics. There's no point in coming up with the most amazing idea to sell your album if it isn't easy to find and purchase.
1: Make it easy to buy: Marketing does no good if your fans can't easily purchase your album. Get yourself some distribution, son! Make sure people can find your website and link through to places where they can buy it. There are lots of services out there which help you sell your album. At the very least, you have to be on Amazon.com and itunes.
2: Email your fans: You have been collecting email addresses right? You should have a table and an email signup list at every show. Your website also needs an email sign up form.
2b: Give them something: Try offering a free song to your email list once a month. Either a live track, or alternate version, keep it fresh. Send it direct to them and you'll keep a much more engaged list.
2c: Keeping two lists: You should have a dedicated fan list, but not all messages are a fit for the same audience. Create a "reach" list as well, to only send big news to. If you're doing a 30 min opening set in your neighborhood, you don't need to tell everyone. When you have big news, or book some big gigs, that's when you include that reporter from Pitchfork, Rollingstone, or Billboard. Have an agent you've been trying to track down? Add them to your "reach" list.
3: Set up a Google Alert for your band name: Hopefully you've already done this. Google alerts are free and easy. Anytime someone writes something good about your group, you should respond. Share their article around on your social networks. They want more views, you want more people to know about it. If they write something negative, you probably don't want to spread that around.
4: First Taste is free: Give away one song to entice people to buy the album. If you can set it up, have them give you their email address, and then email them a link to the song. That way you have a way of keeping in touch with them in the future.
Now your basics are covered. You're collecting addresses to build your fan list, your website is setup, and your album is available to purchase through a bunch of places. It's time to get the word out and play some shows.
5: Play on the back of a truck: Drive around your home town performing your new songs. You'll attract a crowd. Make sure to plaster your ride with the name of your band so they can find you. When you finally stop playing, or get to a red light, make sure you have albums to sell and cash for change. U2 rented a flatbed truck to rock and roll their asses around NYC. Maybe you should start with a pick-up truck. Remember the old timey mayoral campaign trucks that would drive around announcing campaign slogans over a megaphone? Be more awesome than that.
6: Play a roof concert: January 30, 1969, The Beatles played an impromptu concert above the offices of Apple Records. Since then, this staple has been recreated by hundreds of other bands. It's a great way to get lots of attention. (Even if some of it is from the police.)
7: Make a guerrilla video in your home town: People love hometown heros, and they love to see places they recognize. This one appeals to everyone. Your local fans will share the video because they recognize the places in it and already have that connection. Fans from other places will see this as a chance to get to know your band on a deeper level. Include shots around your High School for extra nostalgia. Hit a favorite pizza place, fried chicken joint or ice cream shop for extra points. Maybe you'll even get some extra love from the restaurant.
8: Get in a fight: Rap feuds sell records. Famous people getting in a fight always hits the news. You don't want to do serious personal or property damage. It's tough to tour if you're shot or in jail. But a little scuffle to get on the news/blogs/reddit? That might just work. If you're hard core, gangsta, or punk, this one's right in line with your image. If that doesn't sound like your band...
9: Partner with a Non-Profit: If there's a cause that's near and dear to your heart, see how you can help them out as well. If they have an upcoming event, offer to perform. Set out a table with merch and albums then make some friends and get good will.
10: Guest spots with other bands: No one says you must only play with one group for the rest of your life. You have friends in other bands. Join them for a few songs on stage, and get a nice shout out. Make sure people know that you're with this other band and you just put out an album. If they like what you're doing, that's another chance to spread the new album love.
11: House Parties: Performing at a house party is where it's at right now. Exclusive, private, no rules. Its the best. Nothing beats the feeling of playing for an intimate audience in a small space. When your fans can literally reach out and touch you, that's going to be an experience to remember. Plus, you don't have to front the same level of swagger. In a small crowd like this you can let down your guard, tell a few jokes. Genuine interaction between people on stage always means more to the audience.
12: Create a Scavenger Hunt: Place clues around town, tell your fans, and then hide copies of your album or USB flash drives. This was a genius move by Trent Reznor for Nine Inch Nails back in 2007. Check out some more of his advice on marketing your music.
13: Stickers with a digital edge: Band stickers have been around as long as people have stuck glue to the back of paper. Try adding a QR code linked directly to your site so people can join your mailing list and download a free song.
14: Join Contests: Find contests and enter them. Some are song-writing contests, where you only submit your work. Others, like battles of the bands, have you playing in front of new audiences. Play shows, sell albums, make cabbage.
15: Cross-promote with other artists: Give them a promotional code to download your album for half price, and have them send it through their newsletter. Their audience is already music fans, so its a natural fit.
16: Exclusive Promotion Codes: Outreach to bloggers is pretty standard. Giving each blogger their own exclusive promotion code is a better idea. Their readers get a deal, and you can see who actually drives more album sales.
If none of these ideas fit your style, you can always try projecting your videos onto buildings, pairing up with a major cell phone company, or just driving a big gold truck.
The best way to promote an album? Play more gigs.