Know when to back off. Many a wayward girlfriend assumes her affectionate attention is welcome by her man until he asks for a little space. The problem with this theory is that when a man is forced to fight for his alone time, he becomes jealously defensive of it and resents his girlfriend, this clingy wench who conspires to steal it from him at every turn. Schedule time for yourself, away from him, during peak hours (Friday and Saturday evenings, or whenever your time is most cherished). This will give your man a chance to kick back with the boys and give you an opportunity to remain your own person.
On that note, be sure to remain your own person. It is vital in every relationship not to define yourself in terms of your significant other. Get a few hobbies. Better yet, join a club.
Convey yourself to your man. Women become emotional and upset far more easily than men, and it is assumed that this is because men have fewer feelings than women. This is not so. Men have just as many feelings as women, but we convey them instantly, unfiltered and often unnoticed, as soon as they are felt. This results in the reputed insensitivity of the gender (as well as the inability of men to relate to love stories, which rely on a great deal of implied, emotions). It helps if you are the same way with your man, telling him the honest-to-goodness truth about what he says and does as it happens. Don't be aggressive or antagonistic. Observe men, watch them relate to one another, and repeat their behavior. Punch him in the arm if it comes to that. This release will make you seem far less unpredictable and moody, making you good company for most men.
Don't assume that doing nice things for your man, even things that are traditionally viewed as subservient, will make him view you as any less independent. This is a big one, and it is especially effective if life is starting to take its toll. If he's had a stressful week at work or a rough string of midterms, wait until he has some free time and make it nice with his favorite meal (served casually; formal dinners require effort on his part and can be a burden). If he's feeling a little down, bring him a serving of his favorite sugary snack food. If he comes home and looks absolutely ravaged, collapses on the futon and exhales deeply as though the weight of the world is on his shoulders, bring him a beer and let him tell you what's wrong. General kindness, without the requirement of reciprocation, will work wonders on a man's mood and allow him to associate the resulting happiness with none other than the caring woman who made it all possible. Most importantly, keep your good deeds varying and changing so they do not become confused for actual submission. You're doing him a favor, after all.
Tips
Do not leave affectionate notes for your man to find in any public place. These can be humiliating, even if he appreciates the thought, and will make him seem less professional and independent.
Do not use cuddly nicknames when anyone else is in earshot, even strangers. I know he's your "pooky bear" when you're alone in your living room, but as far as the rest of the world is concerned he should be King Richard the Lionheart, Chuck Norris, St. Paul, Rambo, Rocky, William Wallace, Sir Francis Drake, Vlad the Impaler, Mr. Spock or "Jumping" Joe DeMaggio, however his taste may fall.
Don't fake interest in something. Either be interested in his activities or leave him to them. Faking interest might thrill him in the short-run, but when your lack of genuine interest begins to show himself he will be deeply disappointed.
Don't assume that you're welcome to hang around your man as he works, studies, or pursues his hobbies at home. He needs to concentrate, and women are generally a negative force on a man's ability to focus. It doesn't matter if you don't make a sound. They can smell you.
Do not call him more than twice a week. I know, the phone begins to whisper to you after a while, telling you that he may be doing something he wants to talk to you about, but you must resist temptation. He needs to feel as though he isn't on a leash, that he can do things without informing you if he so chooses. Calling him on a daily basis establishes you as controlling, nosy, and, worst of all, clingy.
When arguments occur, do not take an air of authority, superiority, or antagonism. Listen to his points and calmly, with no sign of your inner annoyance, make your rebuttal. Not only with this help to diminish squabbles, but he'll be more likely to concede future arguments to you, knowing that you won't rub his face in defeat. Win graciously,lose graciously, and hopefully he'll soon follow suit.
Men like it when their women look good, just like women like their men to have money. It may be shallow, but it's true, and I know it doesn't feel like it sometimes, but looking nice for a man is a lot easier than supplying money for a woman. For example, change your hairstyle every now and then to see which weave elicits the best compliments, then wear it the way he likes.
Buy practical presents. Men don't usually like candles, soaps, decorative items, posters, and especially clothing. I know it's cliché, but buy him tools, man-toys, or tickets/subscriptions to things you know he'll enjoy. Also, you know the difference between what your man actually enjoys and what you want him to enjoy. His birthday is not the time to foster that taste for Don Giovanni you've been hoping he'd pick up.
Be honest with him. If you like Salsa dancing and want him to try it, ask him, but let him know that you won't hate him for saying no. If your dream is to live in Scotland one day, tell him so he can make plans accordingly. Some men don't want to date a dominatrix, so clue him in before you cuff him to the bedposts. The possibility that your man disagrees with some of your opinions is the risk you take for having them in the first place, he'll be more upset learning about things he doesn't like if you've been hiding them from him.
Watch your language and tailor it to your guy's ear. Don't say, "Do you want a Coke?" or "Do you want me to get you a Coke?" Both of these imply that he's putting a burden on you by replying in the affirmative, so he would feel inconsiderate to say yes (except in certain circumstances or when asked properly, but these should only be attempted by professionals). Instead, try "Would you like a Coke?" or "Can I get you a Coke?" The wording in these questions send off red flags in a man's mind, letting him know that the speaker is offering to go out of her way to do him a favor. Knowing you won't loathe his response, he should tell you honestly whether he does or does not, in fact, want a Coke.
Warnings
Do not let your efforts to please your man turn you into a doormat. Remain your own person, remain independent, and don't suffer abuse, ingratitude, or being taken for granted. When a man takes his woman for granted, all the effort in the world won't keep him happy since he already expects all the effort in the world. Drop him and find yourself a sweeter, more appreciative male. Trust me, they exist.
All men are different, and this advice won't apply to every one of them. The best way to know what makes a man happy is to ask him.
