Seneca is best read slowly, one problem at a time.
The letters range across time, anger, grief, wealth, friendship and death. Their value is practical when the ideas become exercises.
Do not binge the letters
Read one letter and keep one claim for the day. Ask where it applies before moving to the next.
Seneca is useful because life is messy
He writes from inside wealth, politics, compromise and uncertainty. That makes the tensions in his life part of why the letters remain worth arguing with.
Prefer sources over quote graphics
Popular attributions are often shortened, translated loosely or misattributed. Use a reliable edition and locate the passage before building an argument around a sentence.
Take one distinction from this page and apply it to one real situation before reading another article.
If you want to read Seneca beyond quote graphics, a good edition of the moral letters is the natural next step. See the Stoic Library for edition notes and Amazon links.