I put off linen shirts for years because the first one I owned creased if I so much as looked at it, and by lunchtime I looked like I'd slept in a hedge. What changed was trying one on in a size up from my usual and realising the crumple is meant to happen, it's part of the point, and once I stopped fighting it I actually started reaching for the thing.
Sizing is where most people go wrong with these, including me the first time round. Linen has almost no stretch, so if you buy your normal size expecting a bit of give like you'd get with cotton jersey, you'll end up with something that pulls across the back and gapes at the button. Go a size up from what you'd usually pick, or look for one cut generously through the body, and check the shoulder seam sits where your shoulder actually ends rather than halfway down your arm. Sleeve length matters more than you'd think too, because linen that's too short in the arm looks like you've grown out of it, whereas a proper length rolls up nicely and stays rolled. If you're between sizes, go bigger. A linen shirt that's slightly too small never redeems itself.
Colour wise, I've learned to trust the ones that don't try too hard. White is lovely for about a week and then starts looking tired unless you're fastidious with it, so I've had more luck with oatmeal, a soft stone, or a faded denim blue, all of which hide the inevitable creasing and the odd mark far better. Dark navy and black can look brilliant but they show every crease like a shadow, so they want a slightly less crumpled weave if you're going dark. The colours that have earned their place in my actual rotation are the ones that look deliberately undone rather than accidentally scruffy.
The difference between a good one and a disappointing one comes down to weight and weave before anything else. A cheap linen shirt is often too thin, almost see through, and goes limp rather than soft after a single wash. A good one has some actual substance to the fabric, a bit of texture you can feel between your fingers, and it keeps its shape at the collar and cuff instead of curling like old paper. Check the buttons too, proper ones have a bit of weight and don't crack the first time you catch one on a doorframe, and the side seams should sit flat rather than puckering the moment you move. The best ones soften with every wash rather than wearing thin, and there's a particular pleasure in pulling one straight off the airer, slightly cool, slightly rumpled, and knowing it's only going to get better from here.