> People tell me my accept rate is low, making my questions less attractive for answering.

Ignore them. You are in no way obliged to accept an answer, and it's completely up to you when and which answer you'll accept. _If_ the comments are impolite, or even repetitive, flag them.

> Should I accept the wrong ones to boost my accept rate? 

Absolutely not.

> Can I mark an answer as wrong?

Yes, down vote the answer.