All guy working in seo field know keywords are very important. So, my question is how I am select correct keywords. and my site easily come in search engine. there is any tools?
You should use a tool like google's keyword tool or WordTracker. Both will give you an idea as to how much search volume there is for the keywords related to your niche.
Its true. Also google "youtube keyword tool" Then search for videos in your niche in youtube. Then plug the most popular and recent video's url into that tool And swipe the keywords. You can also use the free version of spyfu. Its dope.
Once you have followed the advice above - consider bidding on these keywords in Google Adwords to ascertain which ones covert your visitors into buyers then optimize for those. Obviously there is a bit more to it than just the above. My point is this; Lets imagine you have an e-commerce site selling "widgets". Naturally the best keyword to optimize for would be widgets - after all this is what you sell. So you spend hours days months and years - maybe, optimizing for the keyword widgets. But what you did not know when you started is that actually "widgets" do not convert searchers into buyers as the searcher is in research phase when looking for "widgets" and not the buying phase. Another way of looking at this; You get a thousand visits a day from google via the keyword "widgets" but only 1 visitor converts into a buyer. That's a whopping 0.1% conversion. On the other hand you get 100 visits a day from google via the keyword "buy cheap widgets" and convert 5 of these visitors into buyers. That's a 5% conversion ratio! I know which keyword I want to optimize for............. Google and wordtracker are great ways to discover keywords. However,the keywords that attract the most searches are not always the ones that make you the most money. Hope the above makes sense.
everybody uses the google keyword tool. If you are a beginner you can include the less competitive keywords and try attracting traffic for them.