Every day and every experience is a chance to learn something. Whether we're learning things that work, things to avoid, things to tweak, etc., every day holds lessons--new or not-- if you take the time to think. I've recently learned a few things that I've, lucky for you, come willing to share. Don't ever put up with anyone who makes you feel like you're not worth their time. Unfortunately, this is a mistake I make repeatedly. There are a lot of variables involved with these types of situations, but the bottom line is simple reciprocity and dedication of friendship. If you find yourself bending over backwards to make a relationship work and the other person puts in zero effort, you deserve better. I've had a problem with undedicated friends since childhood, but I've made a lot of progress here since I learned how to respect myself. Once you realize that you are worth people's time (sounds simple, eh?), you'll begin to demand more from people. I don't mean that you should have your friends show their dedication to you by bringing you coffee in bed or other stupid things, but you're probably not going to experience the joy of healthy relationships until you acknowledge that you should be as much of a priority in someone else's life as you make them in yours. As cliche as it is, you're a unique individual who brings your own set of skills, quirks, traits, etc. You deserve to be appreciated.
"Be who you are and say what you feel, because those who mind don't matter and those who matter don't mind." --Dr. Seuss
*I'd like to follow this point up by stressing the importance of not giving up on relationships quickly. If you feel that you're not ranking where you should be in someone's life, tell them. Have a discussion (not a shouting match or fit of tears). If you talk about what's bothering you, set an expectation of how things should be, and nothing changes, then you need to start re-evaluating the relationship. Every relationship will have compromise--there's gotta be some give and take--but don't settle for being a doormat. No one deserves to be walked over, taken advantage of, or ignored.
Stay positive. This sounds easy enough, but every day life has a way of beating us down and numbing us. For most people, the majority of the news we hear in a typical day is negative. As my dad always says, PMA: Positive Mental Attitude.