If the restaurant is around here I don't look at the websites. Most don't have one and I know what they offer.
If I am going elsewhere I do a google search to see what places are near where I want to eat.
Sadly the better the website the more inclined I am to think they know what they are doing. I read as many reviews as I can knowing that people who are ticked off are more likely to post a review than someone who is satisfied.
I also check the menu. I won't go to a place that doesn't have some kind of a menu online.
Separated into the various meals is high on my list. A breakfast menu is not needed most of the time as I am there most often for dinner. A meat, fish, pasta breakdown is often useful. I like looking a their special of the day menu. It gives me an idea of the caliber of the chef.
Prices are helpful. My daughter wanted us to meet int he western suburbs for Mother's Day. Most of them had a buffet. When I saw the prices were at $50 or more I told my daughter that we would have to go somewhere else. I don't mind paying for the special occasion but my wife would not enjoy her meal and since she just had surgery she certainly wouldn't have eaten very much.
Reading what is in the various dishes is helpful. We usually have 2-4 dishes that she say we woulds like to try. 3-4 dishes we know we would not like because of what they have in the dish. Naturally when we get there we change our mind completely.
A few photos of the place is helpful. Of course that is when the restaurant is at it's best and not on a hectic Friday night.
Knowing how long the place has been open and how long the current owner has been there helps us decide.