Well injecting wise I just whip it all out and get on with it. Mostly because I like my food and there's no messing when it arrives I just want the food 🙂. I had one very interesting incident with a stroppy lady in Starbucks but generally the only people who take any notice are kids and I'm like a magnet for small children anyway (they're known to just plonk themselves on my knee on public transport and start chatting to me). With kids I just show them what it is and explain. Occasionally their parents look mortified but I tell them it's perfectly OK because they're injecting insulin too, it just happens that they can't see it, all very natural. I was asked in a very expensive restaurant to inject in the loo, my answer to which was absolutely not, and it led to a very cheap meal because the manager refused to let me pay when I very gently pointed out the error of their ways. I wasn't even complaining. 99% of the time you're more aware of it than other people, and the 1% of the time when someone else is paying attention it's usually just curiosity in my experience.
Insulin dosage wise, that's the bit I found most challenging at first, my brain is very precise and not made for estimating, my Goddaughter who has Aspergers reckons my inability to cope with estimation proves I've got at least a toe on the autistic spectrum. Folk don't often understand it, but my brain is very unhappy with a lack of precision. So here's what I do. In a restaurant I'm likely to eat a pudding for example, so I tend to bolus for about 40g of carb for that since pudding wise I'm boringly consistent and specific, I only like frangipani/almond tart, tiramisu, and profiteroles really and they tend to be on the lower side of the high carb fence, plus I have a natural off switch with portion size. Things like chips I use the carbs and cals app to have a guess with, and it I'm totally clueless I go with a conservative guess and then correct later. You get an eye for it eventually. If I'm going to a new restaurant I look the menu up online first and decide what I might like and any really unfamiliar item I look up the carb value online to give me something to work with. Those of you who are currently thinking "sweet mother" at the level of preparation....welcome to my brain, it's like this all the time 🙄, and this is why that daft "handful" or carb portion method is like the equivalent of asking me to hack off my own finger 😳, well that and I'm six foot tall with the (well manicured) hands of a lumberjack, I could fit the whole day's meals in one of these beauties 😉
The more practice you have the more comfortable you'll become because there's less estimating involved, you build up an internal knowledge bank of meals you're likely to encounter. Careful with the fish and chips though, there's often a huge amount of fat which slows digestion down massively, with something like that I split the bolus and do half up front and half later when my body has got over the shock of consuming my own body weight in fat 🙂