Hi Joanne,
Another possible reason is that some of the so-called poor quality backlinks are actually the reason why you were ranked on the first page. However, after Disavowing these links could have caused you to drop in ranking. For that reason, many people don't recommend using Disavow tool outright but try to remove the links manually first.
In addition to the above suggestions, maybe try the following:
- Add separators in the title tag to separate keywords
- Image Weight - you can either use Google's Tool or WebPageTest to check out the speed of your site and what needs to improve
