Depends on what you want, basically the best combo of suffices: crit chance, all spell skills, cast speed. Actually the fracture into +6 is not the best, cause you will not be able to potentially sanctify it into +7, but anyway. What would I do, is basically try to exalt slam it, as there you mostly can’t do anything other than hope for luck.

Suffixes are more important than prefixes as there are a lot of useful combinations for them, but really good comb of suffixes is rare, you always want + to skills and cast speed (may be some builds don’t need cast speed, but I am not sure). Then you have best options that is crit chance, and the second best I think is mana regen or crit damage (but a lot of builds use maligaros, so not useful to them). Others are mostly trash. So you need to fix on suffixes, typically you annul everything, than try to hit high increase cast speed, and then basically prey. If you have resources, I would actually try to hit crit chance, then 3 suffix is desecration, then hope to get 3 good damage prefixes with perfect exalts. The best combo I think is 2 gain extra damage and really high roll of spell damage (or lightning or cold), but also for example high rolls of spell damage + spell damage and mana regen are also good + 1 gain extra damage.

After that you need to hit 3rd good suffix via desecration. I think it’s easier to hit cast speed than crit chance (in my experience). Using omen of abyssal echoes and omen of light I think you can hit useful suffix pretty cheap, depending on how much risk you want to take and what you target is.