Give each language a real URL
English and Arabic pages deserve separate, crawlable URLs so people can share the right version and search engines can understand the relationship. A language switcher should preserve the equivalent page whenever one exists.
Design for expansion and compression
Arabic can change the length and rhythm of a message. Test real translated copy early, allow components to grow, and check navigation, buttons and cards at the sizes people actually use.
Respect reading behavior
RTL is more than flipping text alignment. Consider icons, directional transitions, order of information, forms, breadcrumbs and the relationship between images and the reading path. Before launch, try switching from an English service page to its Arabic equivalent on a phone. Then enter an email and a Qatar phone number in the Arabic enquiry form and check that labels, values and error messages remain easy to read.