Here is my list of 20 things you can do to keep a happy dog :)
1. Go on regular walks, at least 3 times a day, in the mornings, afternoons and evenings.
2. Maintain a healthy weight and make sure you are feeding high quality dog food.
3. Always offer fresh water. Dogs usually drink too less, so by offering fresh water they'll automatically drink more.
4. Go once or twice a day on a long walk.
5. Teach him new tricks. Dogs love spending time with their owners and getting yummy treats.
6. Switch up his toys. It'll be like he has a brand new toy each time you switch them up.
7. Go regularly to the vet for check ups.
8. Keep your dogs fur in a good shape (especially long furred dogs) and brush him a few times a week.
9. Trim his claws when necessary.
10. Play with him as much as possible. Try out new games like hide and seek or "find the treats".
11. Drive to a lake and go swimming with him.
12. Give your dog attention, pet him, talk to him and make him feel special.
13. Wash him and give him baths when necessary. But don't wash him too often, otherwise he might develop skin problems.
14. Go with your dog to visit family and friends. He'll love the cuddles and the attention.
15. Do outside activities, go on a hike, play games outside.
16. Don't force him to do something he doesn't want to or is scared of.
17. Try to spend as much time as possible with your dog. There are many cafés and restaurants that allow dogs so there isn't always the need to leave your dog at home.
18. Never punish your dog. Only use positive reinforcement instead of negative.
19. Feed him twice a day. If you feed your dog only once a day it's usually not good for his digestion.
20. Last but not least, dogs have a need to run every day. Some great ways to let him have some running time would be by letting him run next to your bike, go jogging, let him have a good play with other dogs or play fetch with him.