Starting a Reaction Channel

I’ve decided that I want to start a reaction channel on YouTube. My plan is to react to a lot of trending videos, probably in music, sports, & I could also do other trending topics as well. Would it be better to cover multiple trending genres on the channel or to pick maybe one or two areas & focus on content from those? Does anyone have any tips/advice/guidelines that I might be able to use to build a successful channel from scratch?

My advice would be to start by covering all the trending stuff. Once you produce at least 50 videos, you will understand more about "what works best and what doesn't."
When one of your videos blows up, start producing more of that type of content, and focus on that niche.
Good luck and share your channel with us, maybe I'll subscribe .

For reaction videos, there is two main ways :

1/ you can rely on CTR and suggestions traffic by making reactions about general and funny topics ( ex : fails, movies errors, etc ). a very good thumbnail is a must.

2/ you can rely on search traffic by making reactions about the most trending/news topics, in this case, the faster you upload, the better you rank.

3/ or maybe you have your own method in mind ?

The best thing is to use a combo of this three ways ( reactions with a funny approach on the most trending videos/topics with a click friendly thumbnail + your personal touch ). in both cases i think it's better to be general rather than focusing on one topic ( for traffic/subs purpose ).

@VladislavRay @PrivateSMM thanks for the advice guys!