Start by getting your dog's attention with small tasty treats. Keep training sessions short and rewarding.

Hold a treat over your dog's nose and move it back between their ears to lure them into a sitting position. 

Clearly say "sit" each time you lure your dog. This associates the word with the action.

Immediately reward with treats when your dog sits. This reinforces the behavior.

Gradually delay giving the treat until after you say "sit." Eventually phase out the lure.

Conduct multiple short, engaging training sessions per day for consistency.