Make sure your pasta is well drained and dry.
When mine ends up watery, it is because of wet pasta!!!
Also, I don't really go for the super-thick americanized sauce.
I have been using the Rao's, and it is wonderful!
It is fresh, truly 'italian' style tomato marinara... so, if you have to have the lump of thick sauce that sits on top of the pasta, this ain't for you.