I’d suggest reading the entire article to get some broader information on this. The math gets to be a bit complex given the different ratios of standing that you can come across between different factions.
For the deepest dive (and best info) on how to work with and manage these, check out The Plan:
The SoE arc is repeatable every 3 months, the penultimate mission gives a significant standings boost to the faction you ally with (IIRC you may get a boost to their allies too), without affecting your standings to their faction enemies.
The mission itself can be tough on newer players, so if you are one don’t be afraid to ask for help in local, more often than not someone will roll up in something huge and shiny* to help out.
That shows Amarr Empire has +5.00 standing towards Caldari State who has +7.00 standing towards Amarr Empire who has -1.00 standing towards The Servant Sisters Of Eve who have 0.00 neutral standing towards Amarr Empire.
This graph shows the Standing Relationships for all Factions: