What are the ways to improve your WordPress site’s speed?

[BoxIT]

Could you recommend me the ways to improve my WordPress site’s speed?
One of my colleagues suggested me these tips:
- Optimize images for speed on FLATsite
- Use faster plugins
- Choose a theme that’s optimized for speed
So, i need to consult with you on what way is right for me and why.
Any inputs?

[MarcoXX]

If you are looking for a top-notch solution for managing your wordpress sites and convert them into static ones, GO WITH them.
FLATsite.com started to offer SPECIAL: pay $1 for the first month! - https://flatsite.com/pricing/