However, weird comment: I have started (well, actually this happened a while ago) to say "grathias" instead of "gracias" when I go to the grocery store/sandwich shop-bakery place. My accent is still kind of untenable, but I try to hide it here and there.
(In case you didn't get that: In basically all the Spain-Spanish that I've heard, the "s"-ish sounds -- made by s, c, and z -- all sound like "th." Unlike what I was told in high school Spanish, it's not a thing they do in Barcelona, because they speak Catalan in Barcelona. Barcelona is just one word that you can hear it in. And "d" sounds like "th" -- entrada is "entratha.")
I still can't make the real "j" sound, which is like the "ch" sound in German, generating somewhere in the back of the throat, or roll an r convincingly.