Very few guys like to be alone. As soon as guys near puberty, those hormones kick into action, and they want to have a girl by their side. It's not only a cuddling issue, but it's also a basic instinctual drive. Guys are judged on their ability to attract and hold onto a mate. Having a girlfriend will prove to people that you are worthy - that you are handsome and smooth-talking enough to have a girl like you. Having a girlfriend means there's someone to flirt with on the phone, someone to go to movies with. It can be exceptionally rough if all your friends have girlfriends, and you are still ... single.
The key here is that you CANNOT look at this as "I need a girlfriend to be complete!" I know it's frustrating, and I know you want to be like everyone else. However, after talking with thousands of young men, I can tell you it simply doesn't work if your mindset is "I need a girlfriend". That puts you in the mindset of being desperate for a girl. Girls can sense that desperation. They stay away. This makes you more desperate. This makes them stay even further away. You dig your own hole.
Remember, there are pretty much the same number of guys as girls in the world. So the girl that is good for you IS out there. The key is to ensure you are in "a good state" to attract her - and that you are in a location where she can even meet you to be attracted to you.
So, step 1. You need to be a person that the girl would want to be with. Girls are hammered every day with warnings about predatory guys. They are warned by parents, teachers and friends that guys are only "after one thing". They are nervous about this, nervous about being approached by a guy. They worry that the guys will be nice for a few days and then solely want to use and abuse them. Girls can be extremely insecure about this issue. And, perhaps, for good reason in some cases.
So you need to AUTHENTICALLY, honestly, be someone that a girl would enjoy being with. This doesn't mean being a fake! But as many self improvement books will tell you, it is about how you feel about yourself. Let's say you spend all day being grumpy, complaining about your life, pointing out all your flaws and yelling at people. Very few girls will want to be around you. Now let's say you work on changing your outlook, on being accepting of those around you. Say you learn patience and tolerance. You learn to see the bright side of things. So now you look exactly the same way - and you are the same person - but now you are a smiling, happy person who genuinely is content with life. That is the sort of guy that MANY girls want to be with! There are thousands of tips on this site on how to go about becoming more happy. You have to naturally, innately be a happy person to attract the most girls. It's something every one of us can work on.
You might think that girls are drawn to the "bad guy". TV shows love to promote this because of the drama. In real life, few girls want to be abused and treated poorly. Some girls tolerate this only because they are so scared of being alone. It's not that girls want a BAD guy. Girls tend to want the "leader of the pack", again for built-in instinctual reasons. They want a guy that can take care of them. That's not to say you have to be nasty - but you should be happy with yourself and content with the way you are. Girls tend not to want guys that are always vacillating, changing their minds or unsure. They are drawn to guys who have given some thought to what they stand for, and are willing to stand up for it. Girls are drawn to Robin Hoods, to Musketeers, to the many movie idols and story idols out there. They are trained to look for the guy who is respected by others, who is not a doormat. I'm not saying to be aggressive - but have faith in what you believe in.
Next, a lot is said in the media about looks. Guys are actually lucky in this regard - most of the emphasis is on girls needing to look perfect, with gobs of make-up, jewelry, perfect figure, perfect breasts, and much more. In comparison, guys are just supposed to wear "normal clothes". They don't have to deal with make-up and implants! That being said, it is worth it to take care of yourself. People want to date someone who cares about themself - not in an egotistical way, but in a "I am a worthwhile person" way. If a girl looks at you and gets the impression that you eat cheeto-s and nothing else all day long, it's not going to give her the sense that you'll be able to take care of her well. You need to start by taking good care of yourself - your actions speak far louder than any words will.
People do make first impressions when they meet. You want that first impression to be a pleasant one. You want it to accurately reflect the kind of person you are. So, for example, if you didn't take a bath in 2 weeks and were super-stinky, you might be the perfect match for a girl - but she might wrinkle his nose when she smelled you and not be willing to move closer to find out. There are many tips on this site about presenting yourself well - brush your teeth, use mouthwash, smell clean but not overwhelming of perfume or aroma. Wear clothes that highlight your good features. EVERY one of us has good features - our eyes, our smile, our hair. Whatever yours are, read up on ways to highlight them. This isn't about spending a hundred dollars on a pair of jeans. It's about showing the girl that you respect yourself and care about yourself. It is the surest way to intrigue her, for her to wonder if she should learn more about you. Few girls will want to get involved with a guy who doesn't respect himself, who puts himself down all the time. As the saying goes, you have to love yourself before others can truly love you.
Finally, you have to be somewhere that girls ARE. If you go to an all male school, and that's all you do every day, the chance of meeting a girl is slim. Think of interests that you have. If you love skiing, join the local ski club. If you love hiking, go out on community hikes. The more that you put yourself into social situations that have girls - and that involve your favorite hobbies - the more likely you'll find a girl who will adore you. I know it's hard. We all are shy. The only way to get less shy is to PRACTICE. Make it a weekly task, to practice at your shyness. We have tons of tips on this site to help out.