Good morning. I would say this.. I would start with “several non-exclusives”. Even if they are “Reality based, or low paying” take the work! Build your confidence, and your portfolio by getting a lot of placements. Those placements will lead to bigger things!!
Do a MASSIVE amount of research/studying of the exclusive libraries, and start pitching after you have gotten your confidence level up. Be VERY selective, and stingy with whom you provide exclusive catalog content; until you see that your tracks will not just sit around waisting away.’
To run concurrent with the non-exclusive libraries would be “RF/Pay Per Cue” libraries, and sites. Select a few, and make sure that you are not infringing on anything contractually (Pond5 would be a top choice to start) with each one of those..
Just my Dos Peso’s..