The list is four pages long, the table is waiting, and the only thing standing between you and a decision is the fear of looking as though you do not know what you are doing. There is a short way through this.
Say the price without saying it
Put a finger on a wine at the price you want to pay and ask for something like it. Everyone in the profession understands this, nobody at the table hears a number, and you have communicated both budget and style in one gesture.
If you would rather talk, give a direction rather than a grape: something crisp, something soft, something that will not fight the fish. Naming a grape narrows the list to whatever they happen to stock, while a direction lets the person who knows the cellar do the work.
What the tasting pour is actually for
It is a check that the bottle is sound, not an invitation to reconsider. Smell it. If it smells musty, like a damp cellar or wet cardboard, or of sherry when it should not, say so and ask for another bottle. That is a completely normal request and any decent restaurant will replace it without discussion.
What it is not for is deciding you would have preferred something else. If you are unsure whether a wine is faulty or simply not to your taste, the fault guide covers what each fault smells like, and saying "this smells corked to me, could you check it" is a fair way to ask.
Glass, carafe or bottle
By the glass is convenient and often the worst value, and an open bottle that has been standing for two days will not taste like the same wine. Asking what was opened today is a reasonable question and the answer tells you how carefully the place looks after its wine.
For two people who want different things, two glasses beat one compromised bottle. For a table of four or more, one bottle that suits most of the food is usually better than several small orders. Half bottles and carafes, where they exist, are underused.
Ordering for a table
Order the white first even if it arrives with the starters, and let the red breathe while people eat. Choose for the majority of the plates rather than the most expensive dish. If the food is spread across styles, a medium-bodied red and a fresh white cover almost everything, and the pairing rules explain why weight decides more than color.
Ask for the reds to be brought cool if the room is warm. A red served at 22 C tastes of alcohol, and it is entirely reasonable to ask for a bucket. The temperature chart is the reference.
Capture it before you forget it
If you liked the wine, take ten seconds while the bottle is still on the table. Photograph the front label, or the line on the list if it went by the glass, and note the price and what you ate. Without the price, a restaurant favorite turns into a disappointing retail purchase.
Restaurant and date: Producer, wine and vintage: Price and format: glass / carafe / bottle: What we ate: Verdict, in one line: Buy for home: yes / at a lower price / no:
Keep those entries out of your bottle count, on a wish list rather than in the cellar, which the wish list guide covers.