In the past, I have used websites like Chegg.com and CollegeBoard.org. They list thousands of scholarships, some of them specific to your field of study but many are also general scholarships. These are usually vetted by the website moderators so very few scams should slip through. If you are nervous about any scholarships, you can do a quick google search on the person or company offering the scholarship, as they would probably advertise these charitable programs as it makes them look good in the public eye. There may also be reviews from people who have previously applied.
In addition, you can check out the webpage of the colleges your are interested in. There are many grants and scholarships available in individual departments of colleges where the competition is far less.
Your high school or community may also have local scholarships again where the competition will be far less than the nationally advertised scholarships.
I hope this is helpful!