Background- Shulchan Aruch O.C. 211
Mechaber a: If the brachos are different, there is no kadima (211:1)
Mechaber b: If the brachos are different, you go by what is generally you favorite (211:1)
Rambam: If the brachos are different, you go by what you want now (211:2)
Mechaber: The above is only true when dealing with brachos of similar specificity, but when one bracha is more specific, the more specific bracha is first. (211:3)
Halacha lemaase: Mezonos is more specific than shehakol and would come first under all circumstances. See the mefarshim in more detail for haetz vs haadama.
[There is a Biur Halacha which cites the Eliya Rabba in the name of the Shela a general practice of people who make a bracha on schnapps before other brachos with more specificity (e.g. haetz). He suggests to their benefit that they really only want the shnapps at first and their desire for other foods is only after the drink. The BH recommends eating the haetz first, nevertheless, since eating after may render the food tafel to the schnapps]