I think these tips are obvious, but I’ll just do this haha.
1. Using padding/margin to position everything
Do not use padding and margin to position elements, once you resize the viewport the elements will flow out. Instead - use flexbox to position elements.
2. Too much going on.
This is poor hierarchy and will make visitors leave your site without taking action. Users have less attention span, so keep a small amount of content, and beautifully present your site.
Not backing up / duplicating a draft of your site before making a big change
Backing up your site before going rouge is a good way to retrieve back an older version if you have destroyed the current one completely.
Low contrast
Websites are mostly made of text, so always keep your text readable by users. I used to do this because I thought that the content was too abrupt.
Example of high contrast and low contrast.
Using jargon
Do not use jargon to sound ‘‘professional’’, speak plainly. If you are not a huge corporation, don’t pretend to be one. Own your smallness.
If you are with a friend having some coffee, how will you speak? Plainly of course.
Writing long lines of text
You see, people don’t read websites, they scan websites to find relevant content and picking out words. Users ignore content that isn’r scannable.
Missing your goal
When making a website, think about what your goal is. Is it a clothing store? Landing page, or a portfolio?
For example, a landing page wants to get users to sign up for their service, so they make their sign up button as obvious as possible.
And another example of a store selling their toys.
Welp, I think that’s all I have. Please do correct me or list anything else I have not listed here.