The first method of distributing your full color brochures is by doing it the old fashioned way and handing them out in person. This was the first experience I ever had with brochure printing, and I'm sure many others could say the same thing. One of the strengths of an approach like this is that you can pick a specific location, and you actually have people there with the marketing material to potentially increase the odds of someone taking notice of it.
The next way of distributing your custom brochures is to find prime locations around town where you can leave some of them. This can be done in the form of leaving stacks of them at a counter in a store for people to pick up, or you can find bulletin boards to put your printed brochures up on. This works well if you know of some very specific locations where your customers frequent that you can take advantage of.
Next comes sending brochures through the mail. There are multiple ways you can go about handling this, and the first is going to be the equivalent of direct mailing. You're replacing postcards with flyer printing and sending your flyers in envelopes, perhaps accompanied by other marketing material. That will obviously be up to you.
The other way of using the mail is to apply a less direct approach and just make sure to always include a flyer with any kind of outgoing mail. Even if you're just paying a bill or sending out some simple correspondence, put one of your flyers in the envelope. You can get a lot of business with a simple method like this, and you don't have to spend any more money on the distribution than what you would be spending anyways.
Lastly for the mail, you can quite literally walk around and put flyers into mailboxes yourself. You get your targeted marketing push but you don't have to spend the same money that you would have had you sent the flyers through the mail. You also can save the costs of what you would've spent on getting envelopes made as well. This will, of course, take more time, so the decision would be yours whether or not you would consider it worth the time.
There are other ways you can get your flyers to your customers as well, and many of them are going to deal with one type of industry or another. I would suggest as a general rule of thumb that you always get a larger order of flyer printing than you plan on using just so you'll have those extra copies available to you. There's no reason to lose out on business because you didn't get enough of them made.