Vendor Extortion - Sleeping Dogs
You'll be in the marketplace next. Purchase some Dragon Kick beverage along the way to recover some HP and increase your damage, then continue following Jackie. Go to the electronics/DVD store vendor and extort easy money from him.
Next, head to the watch vendor. He'll refuse to give you money so beat up his sole guard and extort from him once more. Next, head to the produce vendor. Beat up several thugs to make him understand and extort from him once more. If you suffered damage, there's another Dragon Kick kiosk or a Pork Bun cart nearby to recover your health.
Head to the butcher this time. Defeat the thugs then extort from him. Then, follow Jackie to the clothes stall. Here, you can buy some new threads for Wei.
If you want some extra damage, purchase the Minor Thug set to get a 5% bonus melee damage. (Knock-Off Hang/ SUI V neck, Very Baggy Jeans, Faux Jiggler Sneakers)
Make your way back to Winston for another scene and to complete the mission.