The short answer on Alternative Girl: pick one anchor piece, keep the palette to two colours, and let the shoes decide how formal the whole thing reads. A convincing alternative copies the proportion and the material, not the logo or the hardware. The details that give a cheap version away are lining, edge finishing and the weight of the fastenings. Repeat one element, a metal, a texture or a colour, and an outfit looks deliberate. The groups below run from the decision that matters most to the ones you make afterwards.

What decides this is shoulder seam, sleeve length and opacity. Everything else is preference. Two from the first group show the range: Ann Demeulemeester's Baptist Printed Standard Fit T-Shirt at $250, and Liverpool Los Angeles's PUFF SLEEVE BUTTON FRONT WOVEN TOP W/ TWIST at $89. The first is the considered buy; the second is the one to start with. Hold it up to the light. Opacity is the thing product photography hides best. The shoulder seam should sit on the bone, not past it. A higher price mostly buys materials and finishing, and occasionally it buys nothing at all.

If the top is the point, keep everything below it plain. From the second group, Elie Tahari's Olivia Utility Satin Jacket ($398) is the one that earns its place, because it works in more than one context without being restyled. The third group is smaller and deliberately narrower, trousers, for the decisions you make after the main one. None of this needs the whole group. One piece from each is usually enough.

There are 20 pieces here from 15 brands, $45 to $755, all in stock when this was written. We would not buy all of them, and neither should you. normakamali.com's SCOOP NECK CROPPED TOP at $45 is the low-risk way in, and otteny.com's Lauren Fluid Knit Trouser Black at $755 only makes sense if this is a category you already use constantly. Read as a set, they get you close to Alternative Girl without any single purchase being compulsory. Nothing here is included because it is famous, and price is not used as a proxy for quality anywhere on this page. If you take one thing away: if you would not buy it at full price, you do not want it on sale.