Seneca, Moral Letters, 98.2b: The rational soul is stronger than any kind of fortune-from its own share it guides its affairs here or there, and is itself the cause of a happy or miserable life."
Stoic philosophers in the past would practice appreciation by making normal things they did harder, such as walking barefoot, or wearing clothes that were older and torn, or not indulge in the finest foods that they could have afforded. A few of them were very rich but would still frequently make choices of less than what they could afford.
It allowed them to appreciate when they did have the better options, and also allowed them to deal with unexpected situations which were not optimal to them, since in the past they had inflicted worse on themselves.
You can appreciate everyday items in your life more too by starting to have the less option. I'm not saying go live out on the street, or don't eat food all day, but start with something small like if you normally would have drove your car the 1-2 mile trip, instead walk. Try not to eat a large meal for lunch, as dinner will be much more appreciated, believe me, the taste will be much better and overall you will be happier even if you feel a little bit more hungry in the afternoon. Buy the lesser car, or lesser tv can be a little more harder to do, but you can't get to that without trying the easier stuff. And you may never get to stage or need to get to that stage to appreciate your life more.
There are many more ways and more extreme ways you could do this stoic action, but I suggest just start with smaller ways and you will be on a good start to learning stoic techniques.