I eat out a lot.

• I often get tap water. If a restaurant charges a reasonable amount for soda, like $1.50-$2, I'll get one. I generally don't buy bottled or canned soda as I can get that anywhere. I want a fountain drink, they're magical, just like keg beer.
• Portions are sometimes too big, but that's great, that means I have 2 meals instead of one. I often factor in the number of meals I can get out of a meal at a restaurant when looking at prices.
• I don't tip, because fuck you get a better job <-- That's not true, I generally tip 20% if the service is good

There are some "good deals" out there that aren't as good as the face value. For example, Olive Garden's all you can eat soup, salad and breadsticks for $4.95 or $5.95 (I can't remember which and I think it changes anyway). $5-6 sounds good for lunch, especially all you can eat, but then a beverage will be $2.50+ at Olive Garden, and tip will be another $1 or $2, so now it's closer to $10+, and you don't get any leftovers.