More times than not this would involve cowriting with the artist themselves. You could also hire a reputable song plugger to pitch your catalog. However this comes at a price. Getting signed to a publishing deal that has relationships with artists and labels is another way to go but like anything worth having is very competitive. I live in Nashville and the city is full of people trying to do this exact thing -- most of them of been at it for years. The last and most important ingredient of course is to write exceptionally good songs. :) Best of luck.