Since you're asking for copywriting tips specifically, I'll stick to content SEO only
Proper keyword research
High quality content. Research and study the top 10 results for your search query to find out what they are doing to get into the top 10.
Fit your targeted keywords naturally and not like spam. First and foremost, you write to provide knowledge to the readers; not search engines.
The first thing I do with clients regarding SEO (especially local serving small businesses) is to set up and/or claim their Google Business profile. Then include that on their site in some way. (my favorite review plugin is elfsight).
That helps tremendously. I also consider anything that helps raise the site's authority and EAT as SEO.
As far as just raw copy, here are my go-to list of things I always do with an initial pass.
Use correct headings
only one H1 per page
proper H2, H3, etc.
Contextual hyperlinks
outside links that add value in context
using natural words as the link anchor (not "click here")
contextual internal links to relevant content that adds value (can be to other topic pages in the cluster, funnel, etc.)
Real words and natural copy. Try to to be too spammy with keywords.
definitely do use appropriate keywords long and short
take advantage that punctuation (full stops, commas, colons, etc.) do not influence keywords and keyword phrases
Make the content on the page readable, especially on mobile
new paragraph breaks every two sentences or so
Add alt text to all images
don't stuff them with keywords or short-hand
understand that this text will be read by a computer generated reader into audio
Take advantage of Squarespace's great GUI for SEO
Review all those settings boxes and fill out excerpts, thumbnails, social sharing images, alt text, meta descriptions, nav titles, page titles, etc.
Always update old content
keep urls intact
refresh old content with new information
H2's are good opportunities for driving incoming traffic
If a page's topic, subject, and H1 are inspired by a search query, scroll down to the bottom of the google results to see the "others searched these topics" links and use those as your H2s.
Make sure the H2's still make sense for the content on page
Reference and link to known outside SME sources when relevant
Use some third-party tools to eliminate poor quality backlinks
When there's a good quality backlink, make a new post/page about it!
Take advantage of third-party writing tools for copyediting
My favorites are
Grammarly
Hemmingway App Editor
AMI Headline Analyzer
Reading the copy out loud to see if you stumble anywhere
Pay attention to technical stuff search engines care about when ranking your content
Font size too small for mobile
Page images, banners, backgrounds, content too wide for window
And other stuff that Google specifically calls out in performance guidelines from Search Console
I'm certain others have mentioned a bunch of the stuff I did, but I included it anyway because re-reading it helps me remember 😉
