This is a way to boldly state your opinion about something. Start your sentence with this phrase to tell people what you think:

If you ask me, I think we ought to scrap the whole project altogether and start over.

People often use this phrase when they're giving an opinion that they think other people might disagree with. It makes you sound pretty opinionated.

If someone has already asked you what you think about something, you shouldn't use "If you ask me"