In terms of market research it sounds like you have identified the niche that you want to target but have come up dry on what to do next.
Working with the information you have given me you seem to want to write about TV shows (nice choice) and need to find a buyer for those writings. The question is then who would buy such work?
Here I would suggest that the people buying such work would be "selling" it too. So I would want to find blogs, magazines or publications that specialize in TV shows. Adding in my own knowledge of this niche I know that there are genre specific sites - for example Sci-Fi has a lot of specialised publications.
So my search in Google would be for pages talking about the shows I think might have some milage. I would start with the most popular shows that you can think of as this will produce the most hits. Depending on the quality of the sites I find I might simply note some good sources or scale down to more specialised to reduce "noise" results.
Once you have a good list of sites that use the kind of content that you want to produce you would need to do what I would do which is to try and figure out if they take freelance stuff. If they do do they accept unsolicited work?
Unsolicited means that you speculatively submit the work and hope that they want it and will pay you.
Solicited means that you approach them with the idea and they commission the work if they like it.
In most cases you are probably going to have to approach the publication editors and ask them about freelance or non-staff writers. The best way to ask this is the subject for another question.
Finally you should have a list of publications and the way that the editors like to get writer leads (submissions or commissions). Then it is all down to you to make the sale.