Forget about rolling with the flow. If you are sure that you don’t want to date the girl anymore, be honest (at least a little bit). Check out the things that you shouldn’t do when breaking up, listed by Men’s Health:

Giving a lot of excuses
On Monday, birthday of that aunt she knows you don’t like. On Tuesday, late meeting at work. On Wednesday, dinner at your mother’s. On Thursday, stomachache – probably because of the previous night’s dinner. The list of excuses continues even on the weekend, when there are sudden and urgent projects at work.

Disappearing without trace
Not returning phone calls; forgetting to reply SMS; not answering the phone.  This strategy may turn against you, because the chance she may become anxious and confused is very high. The result? The number of calls, messages and emails will be even higher.

Saying “It’s not you, it’s me”
The most hated sentence ever does not seem to fall out of use, both for men and women. But, if you prefer not to be labeled as a jerk, please, don’t say that.

Being boring
You decide to be rude to her friends; talk about how much thinner she was at the beginning of the relationship; say good things about some ex-girlfriend; complain about her mother... Honestly, in that way, it will be easy to get dumped. But, isn’t it a lot harder?