This is a very common mistakes. Spanish people tend to translate the word people as “gente” which is singular in our language. However, as we saw in mistake 1, ‘people’ is the plural form for ‘person’, thus the verb has to be plural. A piece of advice is to think of ‘people’ not as “gente” but as “personas”. You will never make that mistake again.
Instead of saying: “La gente que vive aquí es muy agradable” you could say “Las personas que viven aquí son muy agradables“. It will become clear that: ‘The people who lives here is nice’ is WRONG but The people who live here are nice is CORRECT.