Actually you are young and you will eventually find a lover. You are also naive, inexperienced and that will change with time.
If you are still reading: These are good things, it is all part of the grand experience of being 20-something and you should enjoy it while you have it. Trust me, 20+ years from now you will look back fondly at this time of your life.
As for your questions:
How do I know if someone is gay or not without having to ask around for people? How can I let people know I am gay simply by looking at me?
Usually you can't tell. I say usually because the majority of gay men in the world are unseen, unheard - they present themselves as 'masculine' or 'straight acting. Usually the ones you can tell are a bit more effeminate, which in many cases they affect this in order to be seen and 'found' by other gay men.
Now the watchful eye of a perceptive person can narrow it down. One such way is to look to see who that person is looking at. When others walked pass a gay man's eye will linger on the hot males longer than on the hot females.
If they are uncomfortable about being 'found out' they will carefully turn their head away and look sideways out of the corner of their eyes when looking at males walking by.
I have a highly tuned sense of 'Gay-dar' But then I am highly perceptive and I observe body language and facial expressions. While I learned how to read people as a way to duck flying fists from my Father and my mother's husband, you don't need that sort of training to increase your perception.
Reading body-language is a good place to start:
http://www.google.com/#hl=en&sclient=psy...48&bih=840 As you can see there are a lot of sites out there on the subject.
Also just spend time observing people. Used to be the Mall was a good place to sit and watch people. Time and experience will give you a decent 'vocabulary'. The more people you deal with, talk to, learn about the larger your internal archive of data grows and the more likely you are to 'guess' what a person is thinking/feeling and what their character is like.
If you are 'straight acting' - Meaning you don't lisp, don't hold your hands as if your wrists are broken or do other 'stereotypically-gay' things, most people will have no clue you are gay. If you do any of the well known things that 'gays' are known to do, you will signal others, even the ones as dumb as posts.
How can I let people know I am looking for a loved one simply by looking at me? How can I let people know I need a loved one?
Again, usually not. Only those who are really perceptive and can tell longing in your eyes can know without your saying.
How do I politely ask if someone is gay?
That depends on the person. There are individuals who will view your asking as being impolite no matter how you say it. For the most part this is a question that should be asked in private as a lot of people will take offense at being asked in a public setting.
Asking '
Are you gay?' is a trick question. Even if the person is gay, they may be hesitant to answer or flat out deny because homophobes ask the question in order to pin-point a potential target. As such answering honestly can open the door to persecution/bashing.
I would never walk up to a total stranger and ask 'Are you gay?' - I would get to know them a little, and throw minor questions at them over time to see what kind of response I get. Lately I have found that the whole 'Gay Marriage' issue makes for a good subject to learn of the nature of the person. Thus '
What do you think about New York legalizing Gay Marriage?' becomes a good topic to learn how that person feels about gays in general.
I have also discovered through the years that homophobes will without fail clue you in to how much they dislike the gays. And you don't even have to ask! It may not be the first conversation you have with them, but eventually if you talk about inane everyday things without dropping a gay bomb, they will bring it up on their own. The more phobic they are, the sooner they guide the conversation to the LGBT and their feelings about 'The Gays'.
How can I put up with my best friend and his wife being all romantic without getting amazingly jealous of them?
This is where experience comes in handy. We learn by doing, in this case you are just going to have to learn by being around and exposing yourself to their romance. In time you will grow a thicker skin, in time you will go beyond intellectually understanding he is straight to emotionally understanding it.
If it is a really big issue with you, then you may want to reconsider this friendship and move away from it a bit. Part of this may be your feelings of rejection - he is 'passing over' you for her, which can hurt. Feelings are part of the animal hind brain and rarely succumb easily and willingly to the rational fore-brain. Time, and lots of practice is usually the solution for learning to cope with ones emotional animal side.
How can I ask someone if they want to be my boyfriend without seeming desperate even though I am?
I have to wonder why it is you feel that it is ok to lie to others. If you are desperate then you have a problem, one that you need to face and deal with (desperation). Acting like you are not desperate when you are is a form of a lie. Not only do you seek to lie to the individual you may have a romantic interest in, you are also trying to deceive yourself.
What you need is to figure out why it is you are so desperate for a boyfriend. Is it because you feel having one will make you happy? If so, I hate to tell you this, but a BF will not be the thing to make you happy - happiness comes from inside, not from having certain people around you.
Thus it is important to understand why it is you feel you must have a BF, instead of being comfortable in your own skin to be alone (Alone and loneliness are not the same thing.
Personally, I strive to not be a liar when it comes to my emotional crap. I used to lie all the time, however it did nothing to make me happier. It wasn't until I discovered the healing power of 'truth' and started applying truth to my life and how I feel that real contentment and even happiness started filling my being.
That took about a decade of excessive drug and alcohol use and a couple three therapists to be understood by myself. Hopefully you will figure this one out without drugs, alcohol, therapists, etc. :tongue:
How can I not wake up a 3 am sobbing from loneliness until I get a boyfriend?
Loneliness is something you are going to have to work through. How? I don't know. Different people find different solutions. I think the basic root of the solution is to become comfortable and 'happy' with the man in the mirror - yourself.
I wonder if you are not seeking an external source for inner peace. If so, I fear you will not find that peace you need.
Again, time and experience will be the thing that teaches you most about yourself and what it is about yourself that makes you feel lonely.
How can I sleep in the first place for the same reason as the previous question?
Why fight it?
I am an insomniac, for years and decades I fought staying awake, trying all sorts of potions and meditative crap (and drugs and alcohol and jogging at 1 am, and such other nonsense).
Eventually I decided to not fight it and go with it. If I am in bed for two hours lying there with my mind full of unhappy thoughts and am unable to sleep, I get up and do something. I have spent many a night playing with Google's Sketch-up, refocusing my mind on making houses, cars, islands, cites... Currently I am working on modeling a paddle steamer.
Our internal 'issues' that keep us up at night are usually unsolvable issues that our brain focuses on and works harder and harder to solve. When we cast out attention to other, unrelated things, our mind stops trying so hard to 'solve' the unsolvable, then tends to come up with a solution - eventually.