Keywords are one of the most important aspects for the success of a hub. Just keep some simple tips and your hubs will be going far on their own. Choice of keyword is important. Choose the best keywords based on the number of monthly searches. Keep an eye on the competition as well. You can't compete with the giants.
Once you have chosen your keyword, use it in your title as well as in your url. Repeat your main keyword in your content especially in the first and last paragraphs. Also add it in the tags.