There are lots of web sites out there with great gluten free info. Celiac.com is one. Elanas Pantry has gluten free recipes, also gluten free girl. Can't think of what others are my favorites and sorry I didn't provide links... If you're going to seriously cut out all gluten, you need to figure out what some additives are made of, because some are made from wheat, etc, and reading labels is crucial. If you're just going to reduce gluten and not eliminate it entirely, then you probably don't need to be as strict with trying to catch every last iota of hidden gluten in condiments, etc.
Regarding your list...Some cottage cheeses are gluten-free, but some contain modified food starch, which can be made from wheat.
I use balsamic vinegar, red wine vinegar, olive oil, etc. I buy organic salad dressings that are gluten free, such as Organicville, Seeds of Change, etc, or better yet, it's healthier to make your own and you know what's in it! I also use organic gluten free ketchup, mustard, etc.
I usually just put spices on my chicken, fish, etc, and grill them as-is, or use olive oil/balsamic marinade, gluten-free dressing marinade, lemon juice, mustard, honey,...you can really get creative.
Oatmeal...when I first went gluten-free I avoided oatmeal because I read that it was not gluten-free. Then I started reading stuff that said it is naturally gluten-free, but there can be problems with cross-contamination, etc. So confusing... So I started eating it again. I've been eating Bob's Red Mill whole oats.
It is kind of confusing, but there's a lot of useful info out there. There are some great Gluten Free cookbooks as well. I'm certainly no expert on this and there are others who are way more knowledgable, but this is just some stuff I've learned on the way to being gluten free. I've found that eating clean with less processed foods makes it way easier to eat gluten free because you know what's in it!
Good luck to you!