Felicia M. answered 01/16/20
Fluent Spanish Speaker with a Personalized Approach
In regards to the rules for Ser vs Estar, the following acronym can be super helpful.
For Ser - consider the following categories
Descriptions
Occupation
Characteristic (this includes personality)
Time & date
Origin & Ownership (where does something or someone come from &/or who does it belong to)
Relationship & Religion
For Estar - consider the following categories
Position (your physical position - as in standing, sitting, lying down)
Location
Action, ongoing (this is when paired with a second verb that has an "ing" ending: "ando" or "iendo")
Condition & health
Emotion
In regards to knowing when to use preterit vs imperfect: preterit is used for things that can be considered "events" vs imperfect is more for "states of being." Imperfect is also used for things that are habitual or that happened for a vague, non-specific amount of time (like "when I was younger").
For more help with other concepts, and explain in more detail each concept, message me and I'll be happy to provide further assistance.