Do you find FB ads retargeting and Lookalike audiences very effective?

I'm a beginner when it comes to FB ads. I haven't been able to any positive results from FB ads. I do strongly believe that targeting can't be done better than what I'm already trying. I do get website visits from my conversion ads but the visits don't convert. I'm wondering if running retargeting ads and lookalike audiences (of visitors) will yield any fruitful results? Creating this thread for discussion purposes.