Tubebuddy is the program my team and I utilize to optimize our Youtube videos. We consistently recommend this tool to our clients as well because it is that good.
We trust Tubebuddy (as opposed to another, similar software) because it is the only one certified by YouTube to work directly within the platform.
It shows you what keywords your audience is searching for, recommends keywords to use to improve ranking and allows you to bulk schedule, create templates, shortcut your analytics and so much more.
You'll be amazed at how easy it is to use and if you're planning on using Youtube as one of the premier media platforms to drive traffic from, you need this!