I am an regular cornrow wearer.
Yes. please make sure they do not braid you too tight. if at any time during any row, something feels too tight. tell her immediately so she can make an immediate adjustment.
I agree the the feed-in method is best for the hairline.
I suggest that you avoid protein prior to braiding and instead use a deep conditioner with heat.
I usually lightly blow dry my hair prior to braiding because I think it makes it easier to make the parts.
I suggest that you take a photo of the style you'd like and make sure you are comfortable with the skills of the braider.
After getting the braids it is important that you keep your hair/scalp moisturized the whole time you have the style.
I use several different things.
1. African Royale Braid Spray (Don't get african pride)
2. Diluted Infusium (leave-in) This has protein properties
3. Olive oil & water in a spray bottle
4. Aloe vera juice & water in a spray bottle.
You must moisturize your hair daily! I usually lightly spray mine with one of these things 2 or 3 times a day.
Personally, I don't DC or cowash my hair in braids unless I've been swimming or until I'm just about ready to take the cornrows out. This helps the style keep better.
I find that as long as you're spraying with one of the things I mentioned earlier. Your hair will be sufficiently moisturized.
You should still wear your silk or satin scarf to bed at night.
Oh and I also oil my scalp every few days with coconut oil.
I have type 4ab transitioning hair. it's thick. But I followed the same routine when I was relaxed bone straight too.
Hope this helps.