Find the right site.
If an extra 30 minutes means you will get the site that you really want, then perhaps it is worth it. On the other hand, the "perfect" campsite does not exist! A convenient docking area is very helpful.
Consider the lesser used sites.
Popular sites (especially island sites) can experience an incredible amount of traffic. At these sites, wood is often scarce and inconsiderate campers have spent time damaging live trees. Give these sites a break and head to the mainland!
Set up your tents first.
Bad weather and nightfall can both move in quickly. The peace of mind that I get from knowing I have shelter is second to none.
Know where your flashlight is before you need it!