If you want to go the traditional publishing route, you have to know how the write a dynamite query letter. The below link from Bookbaby and Chris Robley will give you some pointers. I also would add mentioning your platform in your letter. That’s a big thing that agents and publishers are interested in – your followers, which equal your sales potential.
In addition, I would suggest you go the self-publishing route at the same time. This used to be a big no-no, but the list is growing every year of authors who self-published first and did so well that they attracted the attention of one of the big 5 (? – is that the correct number) publishers. And it a one way to build that platform that publishers like to see.
It also helps curb that itch to see your stuff in print (or on an ereader or both!) and frees up your energy to go onto your next masterpiece!