My site load is very slow. How do I diagnose and optimize?

I’m having trouble with
My website homepage loads very slowly. There is a visible white screen for a few seconds before the site loads.

Site link

How can I optimize to load the site faster. Not sure what the next steps should be.

I’ve improved the performance by taking the following steps:

  1. Reduce the image size to just the right size.
  2. Using only one type of web safe font, in my case I am using Helvetica.

I am still getting some reds, would appreciate help rectifying them. Thank you in advance.

I removed the wix video carousel from under the fold on the main homepage. This has solved the issue.

I used the wix pro gallery instead of the wix video carousel.

Very unsatisfied with the lack of control over when JS scripts run.

The issue is back for no apparent reason. It turns out the problem now is when a logged in user visits the homepage.