According To

 Typical mistakes: 

According to me, the interest rate is too high...

According to her opinion, the republicans are going to win...

We use 'according to' when we want to say that our info comes from some other person, book and so on. It means something like 'if what A says is true'. 

Examples: 

According to John, the president of that country is a real tyrant or dictator...

According to the ticket, the plane takes off at 10:30...

'According to' is not generally used with words like view or opinion. We say in the Govt's view, in her opinion, etc. Note also that 'after' isn't used in expressions like these. Typical mistake: After my opinion...

In my opinion, the interest rate is too high...

In her opinion, the republicans are going to win...

About To

 

 'About to + infinitive' means 'going to very soon' and/or 'just going to'. 

Examples: 

Don't go out now - we are about have dinner. 

I was about to go to bed when there was a knock at the door.

*In US English, 'not about to' can mean 'unwilling to'. 

Example: 

I am not about to pay $100 for a pen like that.