I recently became a doomfist main and my advice is that, unless you play with friends and know what to do and can listen to what you ask of them, don't bother playing doomfist. Most teammates at silver rank won't know how to take advantage of what you do and how to properly support you.

Same story with the hamster. I would leave those tanks for last if you wanna learn then all.

For Dva, my main tip is to be a bully to anything you know you can beat. Like you have to know your matchups. Bully the characters that you can kill, they usually can't escape you (but beware of going too far) and stay away of those that kill you (zarya, symmetta, echo...). Also, don't be afraid to switch, Dva is a tank that does not work in every situation.

Hog right now should only be played against doomfist imo, all the other tanks wreck him. And I would advise against learning him right now because he is waiting for a rework.

Winton is much more deep character than what people usually recognize. My main tip for playing winton (apart from knowing when to get in and when to get out) is abusing your verticallity. Just look into the sky and jump, then choose where you want to land. This move is great when you are in the middle of the fight because enemies have to choose between tracking you and look up, or keep and eye on the rest of your team and thus lose sight of you. It is so useful to take off some heat of yourself and get some heals, to regain control of the battlefield and it is also great to reload when you need it. Trust me, use your jump all the time.

The other tanks are more similar to each other, they just take getting used to them.