1. When you met someone and you are not acquainted too much, you can use the phrase "oye, me agradas" which can be roughly translated as I like you. It will not be misunderstood, it will only give the idea that you like the person and you feel like you might get along.
2. For more emphasis, you can say "me caes bien" or "me caes muy bien" which literally means "you fall ok on me" but I know that makes no sense, however in most spanish speaking countries this is understood.
3. "Me gustas" you can use it for a girl you think it's pretty or you find attractive, you tell this to a guy and will instantly walk away from you! or block you if you are chatting.
4. You can try to be more detailed on things you want to point out, things you like, "Me gusta tu forma de pensar" or "Me agrada tu forma de pensar" - I like your thinking - with this phrase people will understand you agree on whatever they think/ "Me parece bien lo que dices" - Not literal but roughly translates as --> I like what you are saying.
5. For something that you really really like a lot, then you use "Me encanta!" and here you are not pointing to anything in specific, actually this is McDonald's slogan in Mexico, instead of "I'm loving it". So for the things that we like the most, we use ´me encanta´ ... it's almost like a superlative, but not exactly.
6. "Me fascina" is equally interchangable with "me encanta". Now if you say to someone "me encantas" or "me fascinas" then an overtone will be understood....