Mobile websites design begins with an important fact. Most of your visitors are holding a phone, probably in a queue, possibly while a toddler demands their attention. They won't strain their eyes. They won't pinch and zoom set up a website. They'll simply go somewhere else.
My aunt learned this the hard way. She tried to order a pizza from a local shop's site, tapped the wrong tiny button, and ended up with three pizzas. "Well," she said, "the neighbors were thrilled." The shop was thrilled too, but that's good fortune, not a strategy.
Give Thumbs Some Space
Screens got bigger. Hands didn't. Put the main actions where a thumb naturally rests, toward the lower part of the screen. Buttons need plenty of room, roughly the size of a thumb or fingertip, with gaps around them.
If two links sit so close that a tap might hit either one, you've built a digital coin flip.
Performance Comes Before Looks
A gorgeous page that takes six seconds to load is a gorgeous page nobody sees. Compress your images. Drop the giant background video. Cut the scripts you added "just in case" three redesigns ago.
Test on a mid-range device with an ordinary mobile connection, because that's real life. The office Wi-Fi is a different universe.
Make Your Text Easy to Read
Set body text at around 16 pixels or larger. Keep lines short. Use short paragraphs and plenty of breaks. A wall of text on a small screen feels like an actual wall, and nobody wants to climb one for entertainment.
Contrast matters as well. Pale gray text on a white background looks elegant on a designer's monitor and becomes difficult to see outdoors.
Trim the Forms
Every extra field creates another chance for someone to quit. Ask for an email, maybe a first name, and stop there. Skip the fax number—yes, somebody out there still asks.
Use the right keyboard for each field, so a phone number box opens the number pad instead of making people hunt for digits. It's a small improvement that can make forms easier to complete.
Tame the Pop-Ups
A full-screen pop-up on a phone is a terrible interruption. Search engines dislike them, and so do humans.
If you really need one, use a less intrusive notification with an obvious close button, and give visitors a few seconds to read before you interrupt them.
Test on Actual Phones
Emulators lie a little. Grab three actual phones, including an older and a newer model, and try to finish your main task on each.
Hand one to a friend who isn't techy and keep your mouth shut. Watch where their finger pauses. That hesitation is your testing checklist, written in fingerprints.