First Tip:
Look at the camera lens, not the monitor. It looks like you're trying to avoid eye contact. I know it's unnatural to look at the lens because it looks like this cold, lifeless blackhole that's trying to eat the universe. However, it's one of those subtle body language things that, well, the whole time the viewer is asking, "Why is she looking over my shoulder?" You need to look at the viewer to "connect" with them. People subscribe because the feel some connection to you and what you're doing.
Second Tip:
There are two approaches to getting people to subscribe: and active and passive.
The active approach involves what most YouTube teachers advocate: the traditional call-to-action. The is an old school sales methods that's been around since someone tried to sell sand to an Egyptian. Some people can do this naturally because it's a part of their personality. Those who aren't just come off a used car salesmen and fake Rolex peddlers. This approach often work well for extroverts and people persons.
The passive approach almost never asks for a subscription or thumb's up or go-buy-my-merch. Introverted people, very personable people. This is my preferred method. My "call-to-action" is nothing more that a black screen at the end of each video with my Web site. It works. People subscribe and buy the stuff from my Web site. Sometimes I don't even do that. Rather I add, "Check out my shop: [my.web.link]," to the comments section add a pin. I also use the description to link best selling items in my Web shop.
Because I shoot in a documentary film-style, a traditional, active all-to-action would ruin in entire video. When is the last time you watched a film or T.V. show and they asked you to subscribe to their YouTube channel or Twitter or buy their merchandise? Yet, films make their money selling merchandise. It's passive. Think of the number of embedded marketing triggers, like a well-placed Walmart bag or Coke bottle. Companies pay tons of money for those spots. Why not do the same for your own products, brand?