Whether you just found out you have Celiac or you're thinking of making a snack for a friend who can't have gluten, you should start your cooking adventure with these "new" basics in mind. Cooking for someone who can't have any gluten or even traces of gluten means you have to rethink what you're cooking with. The "Shopping" section of this site covers brands and different "g-free" products, but you should take stock of any items you were planning on using first. Seemingly minor products - think soy sauce and blue cheese - are now questionable in the world without gluten.
For those who have friends/family or were themselves diagnosed with Celiac, the first thing you'll want to do is raid your kitchen/pantry. Flavored rice, tortillas, beer (I heard that, no swearing), sandwich meat from the deli, canned soup - everything should be double checked. All purpose flour is a definite no, and you are correct that your pretzels should head out the door as well. At my house we piled up all these items that were no longer bueno and donated them, which you could do a a local supermarket, food bank or other nearby donation center. Then it's on to the tricky part - finding and buying clearly gluten free food.
In some stores you'll find gluten free food without a problem - my local Hannaford and Shaw's have dedicated aisles. At those stores and others though - Trader Joe's and Whole Foods I'm lookin atchu - there's a seeming disarray of G-Free products mixed among everything else. While this can make the process seem a bit more normal since you're not limited to one aisle, it also can lead to a bigger headache. Who decided that certain gluten free chips are in the G-Free aisle while the other half are in aisle seven? And why did you do that Steve? It's always Steve.
My local Wegman's has a mix of the above, with a G-Free aisle as well as products around the (mall-size) store, but I forgive them because they have little "G" markers on all of their products that are certified gluten free. This also saves time since it you don't have to check to see if there's any risk of cross-contamination either!
Once you have all your new special g-free products, make sure to read up on how they should be stored. For instance, I followed America's Test Kitchen's gluten-free flour blend, which includes a range of items that have different storage instructions. To save myself the google each time I whip them out, I cut name tags into four pieces and labeled them.
Finally! You're good to go. Credit to you for getting the prep over with now - go enjoy a g-free bev (okay fine you can have two).