
Having pitched an Alpkit Rig7 not very well at the weekend, I had a look at Stuart's guide (in two parts) to it on the review/blog section here and noted that he only mentions the bowline for attaching lines to the tarp but not other useful knots. Coming from a climbing background I know a few knots and hitches but they aren't necessarily ideal for tarps.
I found this site http://www.netknots.com which has clear instructions on how to make most knots you might need. So Bowline: http://www.netknots.com/rope_knots/bowline/
Unless you manage to pitch on ground that has uniform density you'll need some form of tensioning system. There's two hitches very similar to one another: the midshipman's http://www.netknots.com/rope_knots/midshipmans-hitch and the taut line http://www.netknots.com/rope_knots/tautline-hitch/
One other that might be useful if you use a hammock is the trucker's hitch: http://www.netknots.com/rope_knots/truckers-hitch/ as it's strong enough to support weight, I've used this back on the farm to tie down hay bales on a trailer, basically it's intended use.
Any others that folk find useful?