How can I improve the security of my own site? Are there any other ways?​

If you mean security to protect against attacks on your website, web security isn't really that simple unfortunately. There are lots of exploits and things you need to be aware of and the relevance and the way you go about protecting against them depends heavily on the libraries and programming languages you're using. For starters, the OWASP top 10 contains the top 10 most common vulnerabilities with websites. Do your best to make sure you're protected against those, and if you have any questions about them, I or someone else can try to answer.

I create my own websites. At first they were primitive but after they got better I needed to protect my clients personal information on the site. So I got a good ssl certificate for a small amount. Completely satisfied with me and my clients.

You can install SSL/TLS Certificates in your own site to improve your website security. SSL Certificates can secure communications between your website server and user's browser by encrypting data transmission between them. You should also use strong passwords for all your site's administrator account. Also implement 2FA for adding extra layer of security. Lastly do not forget to perform regular backup activity. This ensures you can easily recover your website data in case of any data breaches.

morningstar122:
How can I improve the security of my own site? Are there any other ways?​

If you have a website with your audience's private information, then purchasing an SSL Certificate from a trusted CA is necessary. SSL encrypts data between the server and the browser. I have one from https://certera.com, and it costs me around $3 a year. you can check out