This is a wonderful age to purchase a watch for your child. Get them to pick a watch that they like with an easy to read analogue face. This will give them lots of opportunities to read the time.
When cooking the dinner, tell them how long it will take to cook (always with adult supervision) and ask them to set the timer for the the oven or microwave.
Estimation games are also a really great, fun way to compare units of time. Ask your child to guess how many times you can complete a certain action within a limited timeframe of say 30 seconds or 60 seconds. Get them to work out whether minutes or seconds would be best suited to count the activity, for instance it might be easy to count clapping in seconds but running or riding a bicycle would be easiest counted in minutes.