A lot of aspects add up to an inclusive web experience. Considerations that might not come to one’s mind in the first place — like the use of inclusive language or providing alternatives or descriptions for complex visualizations.Or, accessible considerations such as providing transcripts for audio content.
To get your site on the best track of becoming truly inclusive, the magical Heydon Pickering has put together an Inclusive Design Checklist. The biggest and most comprehensive one available. It includes items for accessibility, performance, device support, interoperability, and language.
Do check it out!