#1 Enjoy yourself. First and foremost, you have to ENJOY doing this. Whatever your goals are, hard work pays off...but you have to enjoy doing it. Having a smile on your face while you're reviewing something can go a long way to change how you sound and show that you're having a good time.
#2 Quality...Quality...QUALITY. How many videos you produce isn't necessarily as important as the quality of your videos. Proper lighting, camera work and equipment go a long way to please your viewers. Think of what you like and want to see in a video before you start filming. Then try giving that experience to your viewers. For instance, if you hate shaky, hand-operated camera work in other videos, then make sure that you use a tripod for your own videos. If you watch videos that you believe look too dark, make sure you have enough lighting in your own videos. The quality of your videos will go a lot further in gaining an audience.
#3 Consistency. Create a consistent schedule for the release of your videos to ensure that viewers keep coming to your channel. Viewers lead busy lives, and if they keep returning to your channel only to find no new videos, they will often stop coming back. If your viewers know when to visit your channel for new reviews, you will have a better chance of gaining regular followers.
Also make sure to create a schedule that works around your time for video production AND your budget. For example, if you only have time on Sundays for some piece and quiet, don't tell your viewers that you will release two videos a week. Try for a more realistic schedule such as two videos a month--and give your viewers a day to check back in with your channel. For instance, you could release your videos on every first and third Mondays of the month. Furthermore, some action figures are very expensive and cannot be purchased each month. Don't create a review schedule of eight figures a month if you cannot afford to buy those figures.
#4 Originality. While imitation may be the most sincerest form of flattery, it doesn't always work out that way for video reviews. Viewers want to watch something they've never seen before. Copying another video reviewer's style does not give them that experience. Examine what is unique about yourself and what experience you PERSONALLY could give to a review.
#5 A Little Research Goes a Long Way. It is unfulfilling to watch a review that tells a person no more information than what they can already read on the box. Do your research on the background of the action figure, and you will give your viewers a reason for watching other than to just view the figure.