My estimate would be around $40-50/hr for you.
But you will have to determine for yourself based on the kind of projects you are looking to do and what clients would be willing to pay given your experience and specialization level.
I prefer working with hourly contracts where you simply track all hours worked through a piece of software that includes screenshots and written memos, so the client always has an overview of the progress.
For fixed-term contracts I factor in 10% extra work due to iterations needed to be done. You can consider the amount of iterations/revisions you offer to prevent putting in too many hours. I charge non-creative activities such as research and communication at 70% of my hourly rate. You can work with an upfront fee to ensure professional conduct and establish some trust with a client. I also advise you to include a Terms & Conditions document stating your rates, cases where your rate or project fee may be changed, the scope of the project and its deliverables, file handling and legal disclaimers.