To get the Achievement Not Twice, But 10 Times. You will have to complete 10 opportunities, the further you develop your skill levels such as; cooking,playing guitar, repairing and athletics for example.The more opportunities you will likely encounter, you will only encounter these if you answer your phone when it rings.To complete a opportunity you just need to do what the explanation tells you to do.
The other way you will get opportunities is to just go to work, this is where you will encounter most opportunities. The criminal career offers a lot of these, I am at level 6 of this career and have already encountered 4 opportunities.
Hope this helps! :) (If any negative votes please explain in comments)