What to do when eating out

I nearly always order things like grilled meats, tossed salad, and maybe a baked potato with butter. Those are all fairly easy to estimate based on cut of meat and approximate serving size. If you need help determining serving size, googling "serving size chart" and looking at the image results should provide you with several (many!) different charts that help you use a fist, finger, palm, etc. to approximate serving size.

I try to add by ingredient for the closest match. If I have a particular type of salad I log all individual ingredients that were in the salad with estimated serving amounts.

I try to check out the menu beforehand, whether online or, if convenient, popping into the restaurant and asking for one (I tend to eat in restaurants that are dine-in/take-out, so paper take-out menus are normal). Then, I'll check the database for something similar. I should mention that I eat kosher and, since the mandatory calorie posting only applies to chains with 20 locations or more, this isn't something I can take advantage of. I think there might be one kosher restaurant with three locations; the rest have one.

I have emailed one restaurant with questions and gotten back helpful replies. (The shakshuka comes in a bun, but you can ask for it to be omitted; the grilled eggplant comes with tehina sauce, but you can ask to have it on the side instead of drizzled on top.)

There are options I don't order anymore, because they aren't in the database and I have no clue how to approach them. Like the hard eggs and vegetables served in a deep-fried dough turnover with a tomato-type sauce drizzled over it that gleams like there's oil in it. Delicious, but if I'm going to eat it, I need some kind of ballpark number to log, lol.

I pick something not over-the-top in calories (i.e., something deep-fried and covered in cheese). I pick a similar entry in the database and just pick the highest calorie option. I'd rather overestimate and then shave off some calories daily for the rest of the week.

I get as close as possible but I don't stress. It happens so infrequently that it doesn't really matter for me. When I do eat out I typically go to the same places and i know the calories from their website. As of Jan 1st 2017, in Ontario restaurants that have more than 20 chains are required to list the calories right on the menu though, it helps.

Immediately order a water so you have something to do other than eat chips or bread until you food arrives. Order the veggiest, meatiest entrees and avoid calories, carbs, fat or what have you. Do calorie/fat/carb/sodium research on the food. When you learn that pop tarts have 300 calories you will never waste your calorie budget on them again when you can eat a moist chocolate cake for the same expenditure. Same for a full sugar soda. Try to order from home so that you are committed to the petite steak or broiled lobster instead of bucket of butter entrees. When ordering in the restaurant, ask for a to go box and immediately put half of your entree in it for the next meal. If taking out, immediately cut your entree in half and put in on a plate in the freezer so its gets too cold to eat now. After finishing your dinner, take it out of the freezer and store it in the fridge for your next meal.
If you friend is having something over the top wonderful, ask for a bite. The first bite always tastes best and that my satiate. My normal sized brother in law is happy to give me a bite of tiramusu if I take him out to eat.

If the nutritional info isn't available then I use entries from a similar restaurant.

I should mention that if I know that there's going to be stuff for mindless nibbling, I pre-log. It may sound a little weird, but I write fanfic as a hobby and I'm used to having conversations in my head with my characters. Talking to myself (not out loud!) is similar. So, I ask myself, "How many mini-rolls from the bread basket/tortilla chips/etc do you think is reasonable? What will it take for you not to feel deprived if everyone around you is tucking in before the main food arrives? Let's log it now." This may not be the same for everyone, but for me, if I've logged that I'm going to have one bread roll, it's that much easier to stick to. It's like "I want it, I planned for it, I said this was all I need and it is."

I try to stick with whatever looks the healthiest, although I know looks can be deceiving. I stick w/ a salad usually. If we are eating Mexican, I always get fajitas and limit myself to one corn tortilla. The chips are always an issue, though.