I have market samurai and micro niche finder. They are great and I sometimes use them, but to be honest most of the time I end using Google adwords tool!
There are many ways -you can find by google search,you could take help of google adwords free keywords suggestion tool,you could check the websites with same stuff and then check their meta tags...through these ways you will get a good list of keywords.
Adwards is the best. And aftel you generate some traffic, I think you should rely on analytics too. See what keywords were used to get to your website and start working with those.
You can check out the free version of Market Samurai. This is a tool that is pretty well documented around here, so if you have problems people will be able to help. Look for keywords with a low level of SEOC (SEO competition). Also, try to target long tail keywords. The traffic you get from those will add up exponentially over time.
the Google adwords keyword tool is by far not the best, however it's a good starting base, use this tool and Market samurai at the same time to research key words that you find, export these into a database and re-collect every month
Google adwords is best tool for keyword research it can tell you how many user search for a particular word and which is most searchable or targeted.
try to select the keywords which are popular but should not have too much of a competition for it. if the keywords that u are targetting has too much of competition then it is difficult to get them on the search engines. so carefully select the keywords. all the best