This is fun to do…
There is probably a dozen ways to do this, but here is the quick and dirty without any type of plugin.
Go to YouTube, select your video. On the right side of the video you will see an box with code that says “embed” and “customize”. Copy the code in the embed box, and paste it in your post. Publish and preview. Note that you can alter the height and width, you can also use alignment attributes to position your movie. (I should note that I do not use the visual editor.)
Here is one for practice. Just copy and paste in a test post, and then play with the sizes for fun.
<object width="425" height="344"><param name="movie" value="https://www.youtube.com/v/K2GLrZSTsI8&hl=en&fs=1"></param><param name="allowFullScreen" value="true"></param><embed src="https://www.youtube.com/v/K2GLrZSTsI8&hl=en&fs=1" type="application/x-shockwave-flash" allowfullscreen="true" width="425" height="344"></embed></object>
…or, go and find a plugin that takes all the fun out of it.
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