Some things I can see:
1 (15 ounce) can tomato sauce
You want to use good canned whole peeled tomatoes. Put them in a bowl, get your hands in there, and crush them very finely. But you have to let that tartness cook out a bit.
1 teaspoon sugar
Try very finely grating 3/4 cup (about one) peeled carrot instead of using sugar. The sugar isn't doing what you think it's doing if you're just tossing it all in together. Very finely grate it, you shouldn't be able to see it in the sauce, you're just grabbing the sweetness.
1⁄4 teaspoon salt
Start with that, you're probably going to need more.
1⁄4 teaspoon garlic powder
You probably want to use toasted minced garlic, crushed using a mortar - or use a few cloves of fresh minced garlic instead.
Here's what I recommend:
Start with a large can of whole peeled tomatoes. Get them in a bowl, crush them. Finely grate one whole carrot into the tomatoes, set aside. Taste them; notice that sour, sort of tartness? It's your job to get rid of that.
Get an appropriately sized sauce pot going over medium heat. Crush your dried thyme into it and let it wake up in the pot for about a minute. Pour in the crushed tomatoes and carrot mince, bring to a boil then lower the heat. Let it simmer for about 15 minutes. Taste it - you want the tartness cooked out of those tomatoes. If it's still tart, give it another 15 minutes. And even another, depending on the tomatoes that you used. When it's not tart any longer, Add your salt, pepper, bay leaf and garlic. Stir and let simmer for a few minutes more. Taste again, adjust for salt. Make sure you cook out that tartness.
Let it gently bubble on medium-low heat, don't touch it for 30 minutes.
Again, taste for salt. If you can't clearly taste tomatoes, or if it tastes sweet, add salt a pinch at a time. Salt, here, is what makes those tomatoes the star of the sauce. Too much and you ruin it, too little and it's bland or sour.
You may or may not want to add more water at this point to thin it out. If you add more water, walk away after doing so and then come back in 15 minutes. Taste again for salt.
Let it cook another 20 - 30 minutes on medium-low heat. It should just be bubbling. Do a final taste - add sugar or salt if you think it needs it, add the basil and oregano then let it cook for another 15 minutes, and it should be ready to go.
Grate in some parmesan (but if you do, hold a little salt back in previous steps, as parmesan is salty).
That should get you pretty close. There's a conspicuous lack of onion here, I'm not sure if you're omitting it intentionally. If not, finely chop and saute one medium onion in a bit of olive oil until it turns translucent before you add the thyme or tomatoes. And, if you use fresh garlic, get it in there with the onions.
