how do you....

Yes nothing more annoying than hearing moans everytime you open a certain webpage;-)

> stop videos from automatically starting to play when you open a website. I've heard something about turning off flash auto play or something- any guidance out there?

It depends on the browser you are using.

Try searching for "Media Autoplay" and the browser you use.

From experience I know that Firefox can't stop some sites that use a Java based player (JW Player == nasty). The only solution I have found for that is to disable java.

You can also use Ad-block - but that removes the whole thing and doesn't give the option to play those clips you might wish to

There is an add on for Firefox called "Flashblock" which stops videos from automatically playing while allowing for easy play should one want to view the video. Works well for me.

Firefox: Tools / Add-ons / Plug-ins / (pick your application)/ Ask to Activate

It helps some.

In Chrome, disabling Plug-Ins works, but it disables ALL plug-ins