How to decrease the loading time of a website?

Optimize Images
Browser Caching
Compression
Optimize Your CSS

Reduce Web page Load Time by:

1. Check the current speed of your website. ...
2. Optimize your image size. ...
3. Use Content Delivery Network. ...
4. Avoid self hosted videos. ...
5. Use CSS sprites. ...
6. Switch off the plugins you won't use. ...
7. Minify HTML, CSS and JavaScript.

 1.Improve your hosting plan. This is one of the simplest ways you can speed up your website: looking at your server
2.Understand HTTP requests. Sites are mainly slow because of too many (or too large) HTTP requests
3. Make images internet-friendly
4.Use plugins sparingly (WP sites only)

Use Image Alt Tag
Use compressed Images
Avoid self hosted videos
Use CSS sprites

Ways to decrease loading time of a webpage:
1. Image optimization
2. Caching
3. Minimize http requests
4. Optimize files

Image Optimization
Try a CDN
Caching
Compression
Review Your Web Hosting

Make images internet-friendly
Use plugins sparingly (WP sites only)
Cut down on external scripts
Optimize JS and CSS files
Take advantage of caching
Eliminate website baggage
Use a content delivery network

    Minimize HTTP requests. ...
    Minify and combine files. ...
    Use asynchronous loading for CSS and JavaScript files. ...
    Defer JavaScript loading. ...
    Minimize time to first byte. ...
    Reduce server response time. ...
    Choose the right hosting option for your needs. ...
    Run a compression audit.

Image optimization
Caching
Code should be light
Optimize files

Ways to decrease your page load time:
Image optimization
Minify JavaScript and CSS files
Optimize caches
Use content delivery network.