I get these questions all the time and thought it would be easier to condense it into a masterpost.
Aries: Frequent eye contact, bold staring contests, wide smiles, curious tilts of the head, frequent attempts to start conversation, friendly jokes and stories, somewhat obvious attempts to get to know you. An Aries wants to break open your shell and see your true self!
Taurus: This sign is a lot more subtle. They seem to give off a welcoming, vibrant vibe when they like someone. Wide smiles, charming conversation, trying to get physically and mentally closer to you.. They will respond to you more than they do with most people, simply put.
Gemini: Wit and humor is a Gemini’s telltale sign. They can act charmingly cocky or witty; they will try to engage you in playful banter. If their eyes light up when they make you smile or laugh, you know they like you.
Cancer: Cancers can be playfully coy when it comes to this. Meeting your eyes and looking away, twirling their hair, smiling more around you, playfully touching your arm or nudging you… They will appear somewhat shy but flirty.
Leo: Leos are bold flirts(of course!) They can be very charming and devious when it comes to showing their affection. Challenging you, playfully fighting with you, making it their personal goal to make you laugh as much as possible… They’re generally pretty bold, but in a curious, almost childlike way.
Virgo: A Virgo craves knowledge when they begin to like someone. They’ll ask you your opinion on things, your likes, your dislikes, your goals, etc. If they make an effort to hang around you, such as asking you to coffee, or sitting by you at lunch, it’s a telltale sign.
Libra: Libras are a challenge, because they are naturally charming and somewhat flirty. When they are sweet and somewhat shy, this is your key. They’ll notice little things about you, or be aware of your needs; if it’s cold, they might put their jacket around your shoulders, things like that. They’ll be childlike and gentle in their affection.
Scorpio: This is actually an incredibly easy one, because Scorpios are very selective with their company. If a Scorpio is very intrigued by you, asking you a lot of questions about yourself and making jokes with you, they like you. They might be sarcastic or bitingly charming. Another telltale is if they’re slightly shy in your presence and do things like biting their lip, rubbing their neck, and blushing. Scorpios are pretty confident in front of everyone but their love interest.
Sagittarius: A Sagittarius’s goal is to make you laugh when they like you; but unlike a witty Gemini, a Sag will do cutesy and ridiculous things to gain your attention. They’re very humorous when they like someone, maybe even dorky at times, but in a way that makes them shine.
Capricorn: Like Scorpio, this one can be obvious. If a Capricorn is slightly shy around you, asks you a lot about yourself, keeps intense eye contact, and generally goes out of their way to talk to you, this is a huge sign. They might be a little bit shy, but they’ll relax when you talk to them more. They’ll probably smile more around you and make more jokes.
Aquarius: They can be pretty forward. Making lots of eye contact, asking your opinion on a lot of subjects, engaging you in intellectual conversations, trying to figure you out… These are all signs. I’ve noticed that Aquas tend to make you laugh and will say a lot of obviously flirty things to gauge your reaction.
Pisces: A Pisces is very curious when they like someone; they want to get involved with you! For instance, they might go to your art gallery or soccer game. They want to show you with actions that they care about you. They’ll engage you in a lot of theoretical conversations and might open up to you about their imagination.