Well, you can see numerous cases when u make good money , but nowadays there are Soo Many of Them that u just get confused. What you should Remember this is A personal point of view, so before making it , see what other say about ur opinion
Bolster your catalog of reviews. Make them professional, have good scripts and camera work. You won't make money from the actual companies whos' products you're reviewing, but you will make money from advertisements on youtube once your vids become popular.