For future readers, I would like to say this. Unless you have been a really bad spammer, porn site, or something just plain horrible, there is no need to move your site to another domain to repair your placement in search engines. You are actually making the problem worse. You lose any of the positive metrics your domain name has amassed over the years at the very least.
Figure out what is dragging your site down or what you have not done to compete and fix it. In this case, the OP used guest posting which in of itself was not necessarily bad depending on how it was done, but also admits that the site lacked updating. Had he not moved his domain, I would have suggested checking inbound backlinks, any duplicate content, and begin posting immediately at least 2-3 per week and post in a focused planned way which I could have described. I would have also recommended building backlinks in simple, consistent, and slow ways/pace. I still recommend these things for his new domain name, however he now has to contend with 301 redirects from a domain he felt was a bad performer. In a sense, he just moved the problem.
In short, unless there is a huge problem like I described in the opening sentence and not just a performance problem, do not move your domain to try and fix search performance. If you want to move your domain, then that is another issue. Fix the problems first. You still have to do the work to fix the performance problems regardless.