Is anyone recommend the best tool for keyword research??

Which is the best way for keyword research doing manually or using a tool??

you can choose Google ad-words tool.
But the main thing is to choose keywords which are relevant to your websites and help in generating more traffic for the business.

Google ad-words tool, i have heard of it and its really good. If you choose the correct keyword, it will help your website big time.

you can use google keyword tool for research. also there is one more free tool available named keyword optimizer pro which generates lots of micro niche keywords