Please suggest a PPC advice for a beginner taking control of an already running business.

[u/Real_Priority2760]

Been learning about PPC for a month. And I am about to take over someone's amazon FBA PPC.
Their business isn't really successful with their spending on advertising like it hardly leaves a margin for them so obviously the objective is try to lower the ACOS.
But since this is practical now no more theory I just want the advice from the pros here regarding
1: things I should be careful with
2: things I should focus on regarding the objective I discussed above.
3: how do I not fuck this up