Meaning trap
get on with
have a good relationship
To have a friendly or comfortable relationship with someone.

Don't mix these meanings
Same phrase, different job.
To have a friendly or comfortable relationship with someone.
Another meaning of 'get on with' is 'continue doing'; compare the examples to keep the meanings separate.
Hear it in context
Notice where the phrase sounds natural.
I really get on with my new flatmate; we have a lot in common.
In my opinion, it's important to get on with your colleagues because it makes the workplace more enjoyable.
Fix the pattern
One small grammar move makes it sound right.
Not: I get on my sister really well.
Say: I get on with my sister really well.
Don't drop 'with'. (American English usually says 'get along with'.)
Which sounds natural?
Tap the one a native speaker would say.
'Get on with' (British English) is how people describe an easy relationship; 'amicable rapport' is HR-speak.
Build natural chunks
Words that usually travel with it.
get on with + person
- my colleagues
- everyone
- the neighbours
- her well
Don't confuse it
Related
Other meanings and phrases to compare.
- get on with (continue doing) — Another meaning of 'get on with' is 'continue doing'; compare the examples to keep the meanings separate.