What I do is:
1) Put all my money in the bank or gyroid. This stops villagers pinging you for money related things like buying or selling.
2) I also only carry my tools, and walk about the town watering flowers, digging up bamboo & pitfall seeds. If someone gives me something, or I find an item, I sell it straight away. You need to keep your pockets clear of things they may want to come over and try to buy off you or trade.
3) Water all the flowers in your town or make paths---just do anything that isn't carrying anything around. Carrying flowers is the only exception, as they never ask to buy your flowers.
Focus on gardening or letter writing. Do those tree planting chores you haven't done in a while.
4) if they haven't pinged you after walking around normally not carrying furniture, you can always try diving for a long time & getting an item off Pascal. After you got your Pascal item, or you've been diving for a solid 5-10 minutes, come back up to the shore and walk in front of villagers (after selling anything you caught diving).
5) Just keep walking about in front of villagers without items & hope they ping you about a PWP.
Notes: You can only stop them from trying to buy/sell/trade items. You can't stop them from pinging you for useless things like questions about whether they are more like a red or yellow rose, or whether they are more like chocolate or pretzels.
You can only optimize the pings, but you can't really hurry up the PWP process, sorry.

I've been playing for over 500 hours & still don't have all the PWP I want.
Tips & Tricks: You can go to the extreme of trapping a villager in a circle of holes. This way after you water flower or go diving they will still be there & you can avoid the other personality types and only walk in front of them hoping to get a certain PWP.
My experience: I've spent hours doing "methods" like the diving method, or trapping villagers in holes, but it's just work & stressful--doesn't always get you any extra PWP.
I'd suggest just playing normally without any bells or items, relax & do some gardening. That's the best way.
Hope that helps!