Reading "living theurgy"

i'm reading a book on neo platonism atm... i need an access point if i want to start preforming ritual magic... as opposed to base sympathetic magic
i read a book once called 'Icons of Power: Ritual Practices in Late Antiquity'
that claimed that theurgy was a development of older pagan rituals
and i'm hopeful that since it was focused on the solitary practitioner that i can backwards engineer it a bit to derive something useful from it
if nothing else some pointers towards forms of meditiation that are a less awkward fit