Many writers decide to use all available means to market their books. They set up a nice web site, they write a blog, they Tweet, they put up a Facebook fan page, they offer to do guest posts on other people's blogs, they send out press releases, they do some article marketing, they put a video or two on YouTube...and often they don't get much of a result.
It's discouraging and at that point many of them give up.
The key is focus. As an example, say each week you have ten hours to devote to marketing your book. If you spend one hour on each of ten methods your efforts will be so diluted that they're unlikely to bring much of a result. But what if you chose one of those methods of reaching people and spent all ten hours on it. It's onl logical that your results will be better.
There's nothing wrong with experimenting with different approaches. In fact I recommend that, so that you can find out which ones appeal to you. Usually these are also the ones you do well. Some people hate being on camera or don't want to spend the time to learn how to edit video, add titles, etc. Others enjoy those but can't figure out why anybody would want to spend time Tweeting.
The "overlap" I refer to in the title of this post is the one between what you enjoy doing in terms of marketing, and the channels of communication your target audience is most likely to use the most.
I happen to like making videos and I think that's a good method for reaching a young adult audience, so that's the method I will use the most when it's time to start promoting my Young Adult novel (I also have to finish writing it...). If I were targeting an older group I might focus on contacting book clubs and reading groups to offer them a sample chapter or maybe a short story with the same protagonist as features in my novel.
Since consistent action is required when marketing a book it makes sense to focus your time and energy on a method that you enjoy and that is enjoyed by the people you hope will buy your book.
(There are chapters on traditional and guerrilla marketing in my book, Your Writing Coach. You can get it from Amazon or your other favorite bookseller as a paperback or ebook).