Plot twists are good ways to catch your reader's attention. They come from nowhere when you least expect it. Either from the not so liked character or from the hero himself makes the best plot twists.
Someone dies (It's always sad if someone you least expects dies from saving someone's life.)
The "good guy' isn't exactly good ( It's always cool to see the 'mentor' or 'best friend' become the bad guy.)
Everything is good and then it all goes downhill ( When everything is peachy and then BOOM everything goes wrong)
The hero is related to the bad guy. (When the protagonist is actually a descendent to the antagonist)
No one is who they seem.(The 'good guys' are actually the bad ones, while the 'bad guys' are actually good.)
There are two ways you can catch a reader's attention. The beginning and the plot twist are the two parts that can catch any reader's attention. Remember, if it would catch your attention then it most likely catch your reader's attention.
Please feel free to help me with some ideas!