Finding that the video you want to embed into your blog is to wide to fit within the page is a fairly common problem, and so here are my tips for how to get around this issue.
Let's use the video below as an example: if we just copy and paste the embed code from YouTube as it is for inclusion on the page, it overlaps the sidebar and as you can see it doesn't look very good :-(
Here's how to change the width of a video so that it doesn't overlap the page:
Click on the embed button and then use the customise feature to select a width for the video you want to embed that is a smaller size than the page width.
For this example, I've set the width to 450px and you can see the result below:
Embedding Videos From Other Sites
Most sites that allow you to embed videos also give you the option to change the width of the video - however, if this is not the case, then you can change the width by switching to Edit Html mode and amending the line of code below (height and width parameters) within the .html code to whatever size is required:
The line of .html that sets the width and height for a video may appear more than once within the embed code and if this is the case, you will need to change all references to the width and height of the video in order to get it to display properly.