calls you / wants you to play games with him / talks to you late at night. a lot of guys have video game hobbies. if they ask you to play with them sometimes or asks to add you on gaming aps or talks to you late at night when they're usually gaming/homework/doing other things, they probably like you more.

lots of people on blogroll seem to be confused lately
so i'll give you telltale signs
for the title

you can take them both ways

if they do this--they probably have a good chance of liking you, and if they don't, then they probably don't. of course, nothing's confirmed.

this applies to shy people, too. [insert tigeryong here] so don't be delulu and be like "nahhh... they're just shy." delulu is not the solulu. being able to move on quickly after being knowledgeable is really important so you don't waste time on people who are obviously not right for you, if you get what i mean.

in general
waits for you after class. this can or cannot be subtle. they can look back at you and slowly pace themselves while you pack your bags to align with you. if they're more extroverted, they would probably be comfortable walking next to you and starting a conversation. if they're shyer, they might linger a little bit or look back at you. either way, this can apply to a friend, but if it's someone you're been talking to and see potential in and vice versa, trust your gut. welp none applies I'm homeschooled.
texts you back quickly / texts a lot in general / initiates conversation. especially shy people--they tend to not be able to talk about themselves, their hobbies, or insecurities well in person, but they will probably be more open with it from text. LOL yeah look at me on Xarcade vs me in person. I can't even hold eye contact with any of my friends for more than a second. if they also talk about themselves and ask about you, that's a good sign. talking about themselves is already a pretty clear sign, but if they don't ask about you as well, i take that as a red flag. just me though it's different for everyone, but in general if someone does like you they will be sharing about themselves and will want to get to know you as well. I can share a lot about myself but honestly when I ask about someone else... well, you know that scene in Goblet of Fire where Harry asks Cho to the ball? Yeah, that's what I'm like while talking to other people. "eryeahIliketodothatdoyou?"
trust the subtle signs. a person who likes you will probably laugh more, walk with you to your classes (even if they don't make it obvious), or look at you a lot. i don't mean "omg he looked at me once he likes me", but if you're sitting in lunch or class for example and they're talking with their friend and then they look over at you, you might have a chance. of course, you can never trust a one-time. That's so true lol.

girls - since i'm a girl and have girl friends and i've been both shy and extroverted, i think i can do well on this accurately
text you back / keeps conversations going. as a shyer person, i have trouble initiating conversation if you haven't done it back, but if you start a conversation, i'll probably text you back and keep the conversation going. ex. if you ask about my hobbies, i'll probably add in a little "wbu?", but if i don't like you as much, i'll probably end it with a "yeah."
i don't know if this applies to all girls but during lunch i tend to walk around with my friends a lot. if you see me walking towards your table and back or detouring to where you hang out, i probably like you. same with other girls a lot.
fixing hair / makeup / etc. if they're in a class with you and you see them doing this when they used to not, you might have a chance. of course this is very general and a lot of girls do this, but if you see them doing it when they used to not, they might be thinking of you. Flec's blog: The dating advice centre.

boys - since i'm a girl and i have no idea, i'll just say some telltale signs my crush did that let me know
he listened to me and little details. we were talking about having pets and he said, "you had hamsters, right // he remembered my birthday // i remember that i had you in a class three years ago". he also listened to small things.
likes social media posts. self explanatory
talks about hanging out with you / future. it doesn't have to be like, "are you free at 8 for dinner", but it can be more like "yeah. i love to drive. i'll take you for a ride one day." even shyer guys do this if they really like you, trust me.
looks at you a lot. also self explanatory
calls you / wants you to play games with him / talks to you late at night. a lot of guys have video game hobbies. if they ask you to play with them sometimes or asks to add you on gaming aps or talks to you late at night when they're usually gaming/homework/doing other things, they probably like you more.
I would legit be like "hey you wanna play FTW or smth" RIP my social skills.

don't completely trust this list--especially the guy section, because i'm not a guy and my crush is probably different than yours--but i'd say it's pretty credible. just because they're not doing everything on the list doesn't mean you should be panicking, but if they do nothing, that might be a sign to move on. if you're a guy and you see anything you want to add or disagree with or anything, feel free to tell me. same with if you're a girl, or anything. everyone's signs are different and i probably left out a few.

don't take this as discouragement also. it's really essential to be aware of your crush's feelings for you so that you don't waste time on someone who doesn't think of you the same way.

you deserve better, right? i didn't add this on the list because it's like, not a sign, but a guy/girl/anyone worth going on a date with is one who is willing to take initiative, talk to you, and convey their feelings effectively.