Agree with vs. Agree on/about vs. Agree to

Agree with means :

1- To have the same opinion about something as someone else :
- Do you agree with me about the issue.
- They all agreed with me .

2- To accept a suggestion or idea:

- I agree with his idea of trying once again.
- I agree with making more effort.

3- To be compatible ,consistent:

- Your story doesn't agree with what the police said.
- His words agree with yours.

4- To be suitable, appropriate, pleasing, or healthful:

- Spicy food doesn't agree with me.
- You look well - the mountain air must agree with you.


Agree on/about something or agree something in British means To agree with people on/about other matters after disusing, to reach a decision about something:

- We agreed on the price.
- They agreed on selling the house.
- My father and I don't agree about/on very much.

Agree to means to accept something:

- We agreed to her suggestion.
- My sister doesn't agree to selling her house.

References

- American Heritage Dictionary.
- Longman Advanced American Dictionary
- Cambridge Advanced Learners'Dictionary