Advice for SEO for Squarespace Site

We have just started on the SEO for our new Squarespace website, and have done a lot of the basics but and would like to get some advice on what to tackle next. We have some detailed questions (i.e. about longtail keywords) and more general ones about how to promote our blog content. Basically would like to have an in depth conversation to iron out a lot of little queries that we have!