FJM is right on the money. Short training sessions are best. And yes, continuous reinforcement is a valid training method. In a strange situation, tell the dog to sit, and give treats one after the other. As long as the dog is stittng, you are a continuous treat dispenser. Dog gets up, treats vanish. Dog sits, back to being a treat dispenser.
One thing I've noticed my students doing is holding a treat, luring with the treat, but forgetting to give the treat to the dog. Give the dog treats. Dozens and dozens of treats. Tiny treats, mind you. My dog's idea of a treat is the size of a pea sliced in half. I have tiny treats so I can give lots of them. I still use continuous reinforcement in high stress situations where I needed to reinforce calm behavior. There is nothing wrong with continuous reinforcement, assuming you know what you are reinforcing.
To predict antsy behavior, watch your dog like a scientist. Watch for what comes before the crazy behavior. Look for subtle shifts in body weight, different facial expressions, ear lifts, tail dips. What comes first? When you know what the first signal is, watch for it. Catch that first signal like snagging a butterfly in a net. The instant you see it, ask for an incompatible behavior, like sit. Then reinforce the sit continuously for several seconds. Praise and release. Keep walking, and when you see your dog throw you the uh-oh sign, ask for that sit again.
Remember to go on training missions. Those are outings where the sole purpose is teaching your dog. 98% of your attention is on the dog. 2% of your attention is on not bumping into things or tripping. On these first few training missions, observe your dog. Your dog is showing you so many things! If you stand still for too long, you get antsy behavior. Do you want to know why? Because... because... ready? Your dog is in limbo. You greeted a person, your dog greeted a person, wow, that was interesting, what comes next? Apparently, nothing comes next. Well, something has to come next. Look at handler. Nope, no instructions. This doesn't feel good. What am I supposed to do? I don't know. No one told me. This feels weird. I think I'm going to jump around like a nut. Or whine. Or bark, or spin, or pull. Because I'm in limbo here. What comes next?
Let's try that scenario again. You both greet a person. You wish to socialize more, so you give the dog a job to do. Sit. That's a job. Sit is work. Work deserves to be paid. So, go right ahead and continuously reinforce the sit. As long as the butt is on the ground, you're a treat dispenser. Anything other than sit makes the treats stop. But, keep your greeting brief. You have a poodle puppy on your leash. Poodle puppy clocks run faster than ours. You think the encounter is 30 seconds. Your puppy thinks that encounter was 3,000 seconds. Keep that in mind as you take your dog places and stay on puppy time. You'll be able to fade continuous reinforcement eventually, but it's ok to give a ton of treats to a youngster. If sit makes treats happen, your puppy will give you a whole lot of sit.