What do you think of that girl?  你觉得那个女孩子怎么样？

Do you think it's all right?  你觉得它好吗？

From my point of view, this problem must be solved at once. 
在我看来，这个问题必须马上解决。

I think you'd better do so.   我认为你最好这样做。

What do you suggest?   你有什么意见？

I'd like to make a suggestion.  我想提个建议。

What about going to the movies?  去看电影怎么样？

Mind your own business!  管好你自己的事吧！

Thank you for your advice.  谢谢你的意见。