Do Negative Keywords Help?

[naman]

I am in the process of planning an online advertising campaign for my website. I want to know the relevancy of negative and misspelt keywords.

Is it worthwhile to bid on misspelt keyword? How safe is it to bid on such keywords.

Is there a technique in which I can select the negative keywords of my website?

Is there any other trick or tips that I can make use of in my online ad campaign?

Please reply after checking my site ( Link in my profile)