Hmmm... my tip... listen more to your body than any numbers. Ya, follow a plan (tho' I never did, just tried to go a little further and a little harder as I could, and I rode with all the club rides all the time 'cause my job or lack thereof allowed me), but pay attention to what effort feels like and where your person level of "I can ride all day like this" is. It will be different depending on heat and wind and whatever. And learn what things "sneak up" on you so you can pay attention to them (for me it's having enough salt/gatorade/bananas so I don't get crampy).