Basic Manners
Encourage behaviours that you like and make them more likely to occur by rewarding them. You can do this with treats, playing, a game with toys, pats, verbal praise, access to things the dog wants like going out the door or being allowed to sniff and explore.
Prevent the dog from engaging in behaviours that you don’t like, you can set them up for success by managing their environment. For example, keeping the dog on a lead or in a crate rather than unsupervised around the dinner table so they don’t sneak some food, or leaving them in a dog-proofed area with things they’re allowed to chew, rather than unsupervised with free run of the house with all manner of things to put in their mouths.