Use colours that contrast
It’s important that colours has a contrast ratio of at least 4.5:1.
Does this look ok to you?
If you can read that you have good vision (if you can’t, it says, “Does this look ok to you?”). This text just misses meeting the 4.5:1 contrast requirements. You will need to use a tool to test contrast.
Tools to check contrast
webaim.org/resources/contrast checker will test an individual colour combination 
wave.webaim.org can check a whole page worth of contrast in one go 
colorable.jxnblk.com is a good tool for designers to find colours that work together
Use colour and one more thing
Approximately 1 in 12 men (8%) and 1 in 200 women in the world are colour blind. Don’t rely on colour to show meaning. It won’t work for a lot of people. Add one more thing, like an underline under link text.