Personally, i'd advise meditation. A pendulum probably isn't a bad idea if you're into dousing, and scrying is another option. Also, look for symbolism in your dreams and try to see if anything jumps out at you. It could be a hint. For a lot of people, their spirit guide is an animal that resonates in them. Keep at it!
Also, if you're not a native american, please don't refer to spirit guides as 'spirit animals' because that term is racist unless you're a native american. I'm not sure of any other cultures that use that term, too.