My 14-month-old has been able to put a pre-loaded spoon in his mouth very well since about 10 months (no mess). I give him lots of chances to practice scooping with a spoon too, but he's not great at it and will mostly just play, so most of his meals that need spoons are fed to him by me, or half-half him holding pre-loaded spoons. I won't give him a fork until he is more agile with the spoon.
I don't have the patience for cleaning up huge messes or for him getting really frustrated because he's hungry but can't get anything on a spoon to leave him to it at the moment. I figure when he's ready, he'll just 'get it'. That's the way he seems to work; he'll be mildly interested in something for a while, but not pay too much attention, then all of a sudden he'll seem to work out "Hey, THIS is what you do with it" and get hugely interested in it and master it in a very short space of time.