There are many ways you can hire a crew. One of the first and best ways to get a wide variety of people interested in working with you on the Rs music videos is in the Runescape forums. Make an ad stating you want to create a group to develop Runescape music videos to post on media sites such as YouTube.
Tell them when you want to create them, how many people you need, what language you want them to type/speak, what their responsibilities would be, what benefits they would receive out of being in the video and any other detail you can give them. The more information you give, the more likely you will be to getting responses from people who are great candidates under your specifications. If you find you aren't getting anyone interested, you might want to rethink your specifications and requirements.
Another place is to go directly to your friends or the clan you are in. Not in a clan? Maybe think about creating an "Rs Video Clan" where you can have the clan events be to create clan videos. Give higher ranks to people in your clan who show and say they can control their tasks and won't let you down.
Hiring friends is great because they usually are close to you and understand how you work and what you are like. However, out of all three choices, hiring members of your clan or to be in your new clan would be the best way to get people to participate in your Runescape music videos. You might have one bad apple that will be disruptive, but most of them will be well behaved and complete what you want them to do, as they are already agreed to do so when they joined your clan.