Most mocktails are bad because they're built wrong. Someone deletes the spirit, doubles the simple syrup, and serves sweet juice in a fancy glass. That's a fruit cup with regret.
A non-alcoholic drink is its own building problem, with its own toolkit. Build it that way and it tastes considered, not consoled.
What alcohol was doing
Carrying aroma. Ethanol is volatile, so it lifts citrus oils, herbs, and smoke to your nose. Without it, the drink smells flat.
Giving weight. The viscous, slightly warming texture of a good Negroni or Old Fashioned is mostly alcohol. Without it the liquid feels watery, however much sugar you add.
Balancing sweetness and acid. Alcohol reads as bitter and dry. It's what lets 0.75 oz simple syrup taste balanced instead of cloying.
The four levers
Most well-built NA drinks pull at least three.
Acid is the strongest. Squeeze citrus fresh; bottled lime has already lost the thing you wanted from lime. Then:
Shrubs: fruit, sugar, and vinegar, steeped. Raspberry shrub and soda is a drink, not a substitute for one.
Verjus: pressed unripe grapes, with wine-like acidity and no alcohol. The closest thing to a 1:1 dry vermouth swap.
Acid-adjusted juice: pineapple or apple plus a pinch of citric and malic acid, for cocktail acidity without dilution.
Bitterness is what makes a drink taste like a drink instead of juice. Almost every great NA cocktail has some.
Bitters. Most regular bitters (Angostura, Peychaud's) go in at 2 to 3 dashes, so their alcohol is negligible. All The Bitter and El Guapo make solid NA versions.
Hop water and hopped sodas: IPA bitterness, great with lemon.
Grapefruit pith and peel. Express the oil, drop the peel in.
Tannin is the lever almost nobody pulls, and it fixes "thin." Tannins are the drying, puckering compounds, and they fake the weight alcohol gave.
Black tea, brewed double-strength, is bitter and tannic at once.
Hibiscus is tart and tannic. Swap half the water in a syrup for strong hibiscus tea.
Red grape juice (Concord is the usual one), diluted, stands in for red wine. Add lemon and a dash of bitters and it's a drink.
Pomegranate molasses: sweet, tannic, almost meaty. A bar spoon transforms a simple sour.
Aromatics replace ethanol's lift at the glass. Express citrus oil over the top. Clap fresh herbs between your hands. Steep toasted whole spices into syrup instead of powdering them into the drink. Rim half the glass with smoked salt. Or make oleo saccharum, sugar muddled with citrus peel until the oils come out; it smells louder than half the bottle shelf. Garnish Like You Mean It covers the rest.
NA spirits, honestly
Most are overpriced flavored water in a heavy bottle. A few earn a spot.
Spiritless Kentucky 74, Ritual Tequila Alternative (margarita only)
Most "smoky" ones (taste like liquid smoke)
NA "functional"
Vibe, not flavor
Three Spirit Livener
Anything claiming to make you feel something
Templates that translate
Negroni to aperitivo spritz. Equal parts NA aperitivo, verjus, and tonic, stirred over a big rock. Verjus stands in for the gin's dry weight; quinine covers some missing bitterness. Orange peel is non-negotiable.
Margarita to lime-chili-grapefruit. 1 oz lime, 0.75 oz agave syrup, 2 oz grapefruit, a pinch of smoked salt, and a thin jalapeño slice, muddled and strained. Shake hard. Grapefruit and chili impersonate tequila's bite. It beats most "virgin margaritas," which are sweet lime juice.
Whiskey Sour to smoked tea sour. 1.5 oz cooled strong lapsang souchong, 0.75 oz lemon, 0.5 oz honey syrup, egg white, a dash of NA bitters. Dry shake, then shake with ice. The tea brings tannin, bitterness, and aroma at once: the best NA whiskey-shaped drink there is.
Mojito to cucumber-mint cooler. Muddle mint and cucumber, add lime, a little sugar, and a pinch of salt, and top with soda. Mint, lime, and bubbles were already doing most of the work.
Ice counts double
Alcohol masks a lot of bad water. Without it, chlorine and freezer burn (the ghost of frozen salmon) come through, so freeze filtered water if you can. Use big rocks for stirred-style drinks, and stir a little less than the boozy version, since there's no high-proof spirit to soften. See Ice Matters.
The glass, and salt
Don't apologize for the drink. Use proper glassware and never call it "just a mocktail." Half the disappointment is the diet-soda presentation.
Don't forget salt. A grain or two of kosher salt sharpens any NA drink with citrus. It's the cheapest upgrade there is.