I noticed that a lot of websites use flash, especially for ads which saps your batt life while surfing. So I installed Safari Adblock and also went into Safari preferences and disabled plugins. Most sites I visit work fine because they have backups for browsers without flash. When it comes to a site with a video, I just renable plugins and refresh the page (no need to quit safari completely). But it added about 45min to and hour of predicted battery life on a full charge.