hmm. I'm going to speak on behalf of guys that actually do want a meaningful relationships like myself. It might not be representative of EVERYONE in that category, but i think i might have a generally good idea and some specific insight.
When girls say they want to get a little more serious all it generally means is A. it would be nice for you to be there for me emotionally from time to time and B. don't stick your dick in anyone else. Unfortunately for guys, once they hear the words "serious," they assume girls are starting to plan a wedding and take you to their parents for thanksgiving. So I guess establishing what you like, expect, wouldn't mind as far as your definition of a more "serious" arrangement goes a long way, to ease a guys worries about having to be on the phone for 3 hours a day and see you 6 times a week. A lot of guys run for the hills because they imagine a zero to hero situation, whereas the girl might not even be THAT into you, she just wants to know things are moving in the right direction, and has some basic expectations that honestly most guys wouldn't even mind.
Another thing I'd like to express to you is take initiative. If you are reasonably attractive there is no reason you should not be going on 3-4 dates a week. Guys have this almost unbearable responsibility in this culture to ALWAYS initiate. Fear of rejection is something most chicks don't really experience in its crushing repetition that guys just have to deal with on the day to day. What makes it worse is girls that actually might like you back, but due to the same shitty cultural norms will act hard to get or behave stoic and cold on purpose. Those girls end up single forever and die alone. If you like someone, ask to hang out with them, invite them over, make fun plans they cant even think of rejecting. Women that initiate stand ABOVE the crowd, because they make a guys life much more easy, and allow them to actually feel wanted for once, something a lot of guys might never experience in their entire lifetime. Is there a chance you will be crushingly rejected? Sure. Welcome to every guys life, forever.
The last point id like to make is this. I've never been in a serious relationship with a girl i wasn't best friends with first. Friends before fuckers is the golden rule that most guys live by without even noticing. When a guy finds a potentially serious match, its usually due to the PLATONIC attraction that's necessary for legitimate intimacy, you know right away when you feel it. You catch yourself laughing all the time, engaging in deep meaningful conversation. You have fun hanging out with this girl even with your pants on the whole night. That's the kind of guy you need to find. Those types of connections are hard to come by randomly, or in the dark corners of a bar. Think of how you met and maintained relationships with your closest female friends? You might have met in class, through other mutual friends, through specific events, organizations, activities that you keep very close to your heart. Use that as a measure of how to find romantic relationships. What activities or topics in life generally interest you? You wont find a guy that wants to be with you for the long run unless hes not interested in a majority of the things you are also interested in.
hope i helped.
PS. dont let people "using" you for sex become an issue in your life. If you dont like casual sex then don't have casual sex, draw a line in the sand. If you are okay with sex minus intimacy in order to take care of a simple biological need (a legitimate opinion of many males and even some females), then go at it until the sun rises. Bottom line, be honest with yourself and your potential partners from the get go. Feeling fulfilled in this part of your life has much to do with your mentality, and how your actions line up against them.