As a kid I learned that if you have foods with different brachos in front of you, you should make the bracha on the more important food first, like say mezonos over haetz. My question is how far do we extend this? If I know I'm going to be having dessert which will be mezonos, do I need to say a bracha and eat some of that before I have my scrambled egg? What if it's not on the table yet? What role does my personal preference for the order I'd like to eat things in play?
These guidelines on which beracha to make first only apply if both foods are placed before you and you want to eat from both of them now (Shulchan Aruch OC 211, 5 and commentators). It certainly does not require you to eat dessert before the main course.
If it's not in front of you, you definitely don't have to get up and go get it.
However, even if it is in front of you, where rules of priority would apply, you still can follow the "normal" order of how things are done in a meal.
For example, a person can eat a vegetable soup (האדמה) for the first course, chicken (שהכל) and noodles (מזונות) for the second course and a fruit (העץ) for dessert. He does not need to switch the order around and eat the noodles first.
Source: ספר וזאת הברכה פרק יג׳ and ספר שערי הברכה פרק יב׳.