Search engines are far from the only places to identify markets. You can go to Amazon and see what is in the recent best sellers list. You can go to Clickbank and find what products have high gravity and relatively few sales. You can go to Dummies.com and see if they have anything to offer in your niche. If they have a paperback product, you can provide the information in a digital format, and piggyback on their market research (this series is an excellent example of niche identification).
Identifying markets is the easy part. There are ever more new niche markets emerging in the health, wealth and lifestyle markets every day. You just need to find which are most worth pursuing and start to connect with them, which brings me to the next skill.