Using 同意 to Express Agreement

Do you agree with me? In Chinese, we don't translate straight from English. 

❌	wǒ tóngyì gēn nǐ. 我同意跟你。
✅	wǒ tóngyì nǐ de xiǎngfǎ. 我同意你的想法。

It makes sense because you don't agree with that person itself, instead, you agree with that person's opinion. Therefore, we have to always say: "I agree with your opinion".  However, you can always just say: "我同意wǒ tóngyì！". 

When expressing whether you agree or disagree with intensifier:

wǒ fēicháng bù tóngyì. ——>  I very much disagree.
我非常不同意。

wǒ bù tóngyì. ——> I don't agree.
我不同意。

wǒ bù tài tóngyì. ——>  I don't quite agree.
我不太同意。

wǒ tóngyì. ——> I agree.
我同意。 

wǒ fēicháng tóngyì. ——> I very much agree.
我非常同意。

You can add different intensifiers to soften or strengthen your opinion! Pretty easy, isn't it?