Above ground vegetables should never be served overcooked with few exception (Winter Squash and other hard, woody vegetables which need full cooking process to soften).
Preserve as much of the color and cook about half of it texture. Start with seasoned hot water.
Do not use baking soda in the water cause will result in extra mushy vegetables and will destroy the vitamine
For cooking potatoes always start with cold water
Do not cook acidic vegetables with green vegetables
Add an acid when cooking high colored vegetable to preserve the color
Ad butter, sauces at the end almost before serving. do not overpower vegetable taste.
For holding vegetables on serving line, cook partial then steam tables or serving dishes will finish the cooking. You also can cook vegetables and chill to heat up later for service.
Do not allow cooked vegetables to stay on hot water because will continue to cook resulting in mushy texture.
Do not mix hot potatoes with cold liquid cause will result in starchy texture.
Ad icy water when draining hot cooked vegetables to stop the cooking process
Cut vegetable the same size to cook uniform
To mix vegetable make sure cooking time is addressed for the type of vegetable you cook . Consider to cook separate hard vegetables from soft vegetables and mix at the end only.
Remove wood like parts from vegetables before cooking
Do not over season.
Cook only young, fresh vegetable