Start with what visitors see first
Measure your main pages on mobile before changing code. Look at the largest visible element, layout shifts, and how long it takes before the page responds. This gives you a concrete place to start.
Serve the right image size
Large images are a common source of slow pages. Use responsive image delivery, provide dimensions so the browser can reserve space, and preload only the image that is truly visible first. Let below-the-fold images load later.
Keep the first render simple
Render static content on the server when it does not need browser state. Add client-side code only to the parts that need interaction, and avoid loading large libraries for small visual effects.
Move optional work later
Analytics, chat widgets, and other non-essential scripts can wait until after the page is usable. Recheck the site after each change so you can tell which one helped.
Make speed an ongoing habit
Test a few representative routes on a mobile connection after meaningful releases. A fast portfolio should feel immediate, remain stable while loading, and keep its controls responsive.