I am in texas - I am also elevated risk. Here is what I do - use drive thru when it makes sense (although that is usually too long), use the curbside options and call the business when you arrive so they bring out to your car (many restaurants have this option). If neither of these are available then I go in, stay my distance (with mask on, don’t listen to the people on this thread) and then when I get in my car before I touch anything use hand sanitizer. About every 3or 4 deliveries I also wipe down the inside of the car (steering wheel, turn signals, gear shift, on/off button, door handles, etc). That’s about the best you can do short of not going out at all.
I don't put food inside the car. I have a hatchback, so it's in the back under the cover in a bag. Basically I touch nothing I don't have to when I pick up. If I have to wait I go outside and open the door occasionally to check if the food is ready. Many places will just bring it out at that point. There are a couple of places I will not frequent because they are too crowded and no one wears masks. One is a take out in the BACK of a bar.
One trick is to call the restaurant and ask if they bring out the food or if you have to go in. If they say come in and you hesitate and say you were hoping not to do that very often they will say they'll bring it out.
When I get the food it goes in the back. I have sanitizer I refill from a pump in my cat door on a carabiner and I use that, also on my phone before I open the door of the car to get in. When I drop off I do the same.
My job gives me two very good quality surgical masks every day. If I leave the building and come back I get two more. I eat lunch in my car so I have a supply of them, which is nice (they're triple layer, close over my face better than the thin ones most people like but I feel they're much better protection than those). I am very careful to only touch the loops and I have a string with a hook to hang one in the air in the car when I drive.
I have no problem telling people to step back or that they're not covering their nose and I have called corporate on chains that have non compliant staff (Burger King and Papa John's just to name a couple).
The worst thing to do is hang out on a restaurant waiting. That's the one thing I try to avoid.
Next, pick something you want off the menu and tell them you'll have that for free and make it to go. If they laugh at you and tell you no, then show the manager the pic you took of him/her with no mask and tell them if you don't get the food you're sending the pic of them to corporate.