Chinese style dumpling tips

If buying pre-made dumpling wrappers, press them to see how fresh they are. Ones that are too old will be a bit hard, which is bad for sealing the dumpling.
2 pounds meat + 2 pounds vegetables is good for about 3.5 pounds of Twin Marquis dumpling wrappers (Shanghai style), my preferred brand.
Re: vegetables, Chinese chives have a very strong smell and flavor; Napa cabbage contains a comparatively large amount of water.
A food processor is a great help for chopping vegetables. Chop in smaller quantities and empty the processor bowl out between the quantities. Don't run the processor blade too long or you will have vegetable mush instead of finely diced vegetables.
Regardless of the vegetable you use, squeeze/strain out excess water after chopping it, before combining it with the ground meat.
Use a bowl of water to better seal the dumplings after stuffing them with filling and folding them in half. Use your pinky to apply the water so that your other fingers can stay dry to press the skin together.
When sealing the dumplings, avoid leaving excess air inside, which will increase the chances that the dumpling will break open when it is cooked.
When cooking the dumplings, be sure to stir until all dumplings are floating. Otherwise, they will stick to the bottom of the pot.