1. Have something more important in your life other than just your boyfriend. It can get annoying if the only thing you want to do is be together and do nothing else. Do something interesting that will occupy and keep your attention, something that makes you feel good about yourself and worthy. It can be a hobby, a sport, or just friends that are not mutual. Being too dependent on each other in a relationship can be annoying and can make you just too "clingy" eventually, which is annoying.
2. Give him space and freedom. A lot of men feel as if they were in a "cage" after being in a relationship for some time. Instead, let him feel and be free, you don't have to interrogate him every time he goes somewhere, who was he with, what did he do, why did he do it etc. Trust is the basis of a good relationship and the best way to keep your boyfriend. Let him have his space and his free time and he'll appreciate the time you are together a lot more. The best way to keep a guy is to keep the door open for him to leave if he wants.
3. Stop nagging, complaining and demanding. There's nothing worse than a girlfriend that's always looking for faults and "errors." Just like women, men want to be with someone that supports and appreciates them, and accepts them as they are. Women that are constantly trying to "change" a guy are ridiculously annoying and can only get a guy to hate you or feel weak for submitting. Nagging won't get you far, instead, talk, discuss things friendly, there's always another way to approach things. Be positive and think positively, in a relationship that you want to succeed, your goal has to be your mans success. If you really love a guy you want him to win, not to lose - so help him by supporting him and giving him energy instead of taking it away.
4. Be direct. There's nothing better than honesty. Speak your mind. A lot of women out there keep things in themselves and expect their boyfriends to "figure it out" or read their minds. Ladies - we are not Jedis, we can't read your mind. Being honest is the best medicine for a relationship, open and tolerant, without having to lie or play stupid games.
5. Treat him like a King. I can already hear some of girls screaming "Why doesn't he treat ME like a Queen first?!" That's a dumb way to think. You have to initiate things if you want results. Expecting things to "just happen" rarely works. Stop being selfish and blaming and expecting a guy to do everything in a relationship. Be supportive and your boyfriend will appreciate it. Give to get - that's what works. If you Really treat your boyfriend like a King in every way possible, he'll feel like a King next to you - and that feeling is addictive. So, he'll get addicted to you - and he'll do whatever it takes to keep you. Give to get ladies, that's the formula for successfully keeping your boyfriend in love with you. Treat him like a King and he'll return it tenfold.
6. Seduce him, over and over again. Just because you've already together for a year doesn't mean you should stop being spontaneous and seduce each other. Make your relationship playful, be seductive and sexy, flirtatious with him, a smile can do wonders. Surprise him whenever you can, make an effort. A good relationship takes work, so invest some time into it, it doesn't just all happen by itself.
7. Look good and even better than you did before. Work out, go running, do aerobic, yoga, pilates - whatever. Working out regularly will make you feel better about yourself and you'll be more attractive to him. The hotter you are the easier it is to keep a guy. It sounds shallow, but it's the truth. Of course, it's not the most important thing, but it's a good base. Take care of yourself.
8. Be more feminine. Really, acting though like a guy, swearing like sailor and not taking care of yourself is just not cool, at all. Believe it or not, a lot of guys out there would find you a lot more attractive if you were more feminine, sexy, smelling nice and taking care of yourself. There's not much more attractive than a scent of a beautiful woman and it will keep your boyfriend coming back for more all the time.
9. Give him amazing blow jobs. A girlfriend that knows how to give amazing bj's is one of the best girlfriends a guy can find. This may sound shallow, but it's the truth. If you can satisfy your boyfriend better than any other woman out there, he'll have a much bigger reason to stay with you (and please you back!). Most women are clueless in bed, and especially when it comes to oral. Learn this skill and learn it well and you'll see how much better your relationship will be almost immediately.