The order that gives results.
THE HONEST ORDER
- Compress and resize images. Almost always the largest single gain.
- Enable server-side page caching.
- Remove plugins and scripts you do not use.
- Update PHP to a current version.
- Fix slow database queries.
- Add a CDN.
- Consider paid optimisation features.
WHY THIS ORDER
The first three are free, take an afternoon, and produce more improvement than everything after them combined on most sites.
WHAT PEOPLE DO INSTEAD
Buy a bigger plan, add a CDN, and enable every optimisation feature available, while serving unoptimised images with caching off.
MEASURING
Record the figures before you start. Test after each change.
That tells you what actually helped, which is more useful than doing everything at once.
WHEN A CDN IS THE RIGHT NEXT STEP
When the first five are done and visitors are geographically distant, or when traffic spikes are the problem.
THE TEST OF WHETHER YOU ARE READY FOR A CDN
Is server-side caching enabled and working? If not, that is the next step, not a CDN.
