Here's an opinionated answer: Toddlers do make a mess.
I don't really think it's possible (at least not in any humane way) to teach a small child to start using cutlery without making a mess, but more to the point: the approach we've used with both our kids have been not to try in the first place.
Getting messy is, in most cases, only a concern to the parent. Staying clean, and to a greater extent, keeping the floor clean, is not an end in itself to most children. So to insist that eating should be a non-messy activity, is to enforce rules upon eating that has no immediate value to the child, and will appear arbitrary. You may be fine with that, but bear in mind that in that case, you are turning eating into an arduous chore for the child. I think there is much more to gain if eating is an enjoyable activity to the child.
Food is novel to children. I think they should be free to explore it. You have been eating for years and years, I bet you're happy as long as it's hot and tastes good, but your kid will likely want to be immersed in the food. Play with it, experience it with all senses. What does it feel like on the skin? Thrown to the floor, will it bounce or splat? They can't see into their own mouth, so they'll spit food out, not because they didn't like it, but because unlike you they don't know what happens to the food when they chew it. They can feel that it's chaning character, it's only natural that they should want to get it out and look at it, feel it, once more.
While I have seen a few toddlers who seem to be naturally mess-aversive - who seem distressed by having their hands and face all messed up with porridge, for instance - these have anecdotally also been the kids who have adapted to spoon use early on, which so I think that makes them exceptions that confirm the rule: i.e. if staying clean is an end in itself to the child, you don't have this problem in the first place.
So while cleanliness may seem like a meaningful outcome in isolation, I would argue that in a very real way, you are pitting it against the joy of eating, and I think that should be taken into consideration.
Some tips instead:
- Use mugs and cutlery that won't break when thrown to the floor
- In most cases, don't use a plate. It'll just get thrown to the floor. If you're eating something that requires a deep plate, use one of those with a suction cup at the bottom, so that you can fasten it to the table or tray, or else it'll get thrown to the floor
- Don't have carpets under your dinner table, they're hard to clean
- You may remove some or all of his clothes if you want to cut down on the washing
- At that age, I've found children are often a good fit in the wash basin, and you could simply place them there sitting up, and pour water on them (under supervision, obviously) to wash them up after a meal.