There are tons of "technical" ways to set your drag. I wouldn't get too much into it. If you really want to know, I will post up what I was taught, but I can't remember ever using it. You will get a feel for it after a few fish. Like Paul said, you can adjust it as you go. Just remember, when your drag is loose and you have a fish on, you want to tighten up enough to get a decent hook set(if you aren't using circle hooks), but not too much so your line breaks...and you need to do this almost simultaneously. This is another nice feature of circle hooks. You just tighten the drag and start reeling, no worry of having to set the hook. In the surf, you don't have to worry about getting caught up on stuff, only where your neighbor is, so you can really let the fish do what it wants and looser is better here
. Rather let the fish run than break it off.