adwords keyword planner tool
adwords keyword tool

From the left sidebar choose your targeted country, language, negative keywords etc. so that it can show you keywords details according to your requirements.

Now type different keywords in the text box, each separated by comma and click on tab labeled as keyword ideas.

Google adwords keyword tool

You will find all the details of your entered keywords that will include local and global monthly searches, average CPC and competition of each keyword. All the information you get from there will help you out to choose proper keywords for your articles.

It will also suggest you relevant keywords (just like in external keyword tool).  You can filter keyword suggestions by fixing minimum local monthly searches and average CPC from the left sidebar.