I smash the garlic to peel it. I don't slice it further. I usually use Hunt's tomatoes, or Costco brand. I use a lot of basil, the wife grows it. I like bell pepper and onion and celery sauteed in it. I prefer angel hair pasta. I use wine while cooking.
No sugar.
The reason why I like slicing it thinly is because when you throw it in with the olive oil to sweat it, it gets all translucent and just sort of melts right into the oil.
I highly recommend you give the canned san marzano tomatoes from Italy a try. They are a little more expensive but not crazy expensive. There are a lot of different brands, just look for ones that are marked DOP and are from Italy. They are a lot better in taste and texture imo.
There's nothing better than freshly grown basil. The store bought is OK, but growing it yourself- nothing like it.
Bell pepper has got to be an American thing. You don't really see bell pepper in Italian or Italian American pasta sauces. I don't think I've ever seen it. Onion is pretty much same as garlic, it's a staple in most pasta sauces in Italian and Italian-American cooking.
Celery is typically reserved for the meat sauces. Like when you do a true bolognese sauce you start it off with celery, carrot, and onion and sweat it in some good butter.
I use wine only when I'm de-glazing the pan, I only use it and a little bit of it in a couple of sauces- like a bolognese or a sunday gravy. Bucatini is my favorite pasta. The key to cooking great pasta is salt that water like a mother- you want it to be as salty as sea water- and cook it a minute to two less than the packaging says and then throw it in with your sauce and let it finish cooking the final 1-2 mins with your sauce. Don't put oil in with the pasta water, that's just nonsense and a waste of oil. And if you need to you can always add a couple tablespoons of the pasta water to the sauce to loosen it up if it's too thick. And I never strain my pasta, I just take it right out of the water with tongs and shake off the excess water and then throw it in the pan with the sauce to finish cooking it.
The better ingredients that you buy the better pasta you'll make. Try to buy DeCecco pasta, it's hands down the best you can get from a grocery store. Try to buy Colavita Extra Virgin Olive Oil or Partanna brand- I've tried them all and those are by far the best I've found. Try to buy the DOP san marzano canned tomatoes. Try to buy the DOP Parmigiano Reggiano cheese- Costco actually has great parmigiano reggiano cheeses from Italy. And Pecorino Romano ones from Italy too. They might seem like little differences- but they are HUGE differences when it comes to the final product.