I have tried so hard to have an LD for a long time with no success. I am starting to feel like I will never have one and lucid dreaming is something that I really want to be able to do. Please help!
For how long have you been trying? It took me more than a year, asd now I finally have some good LD’s. Don’t give up!
Lucid dreaming IS possible! 
Don’t get discouraged, no matter how long you’ve already tried. Some people get their first LD on the very night where they have just heard about LD’ing, some may need weeks, month or even years!
You said you tried hard. LD’ing needs a certain amount of effort of course, but there is also the case of trying too hard. It’s this small line between too less and too much you have to maintain and this is a very personal thing and might need a lot of time and trouble-shooting.
My suggestion is, if you feel like you’re running against a wall with your efforts to get a LD, take a break. Just stop with everything related to LD’ing which bothers you and creates a negative feeling, some sort of stress or anger or whatever. If you feel like you want to wipe the slate clean, are motivated and are sure that you believe in yourself, come back to LD’ing and start from scratch.
Don’t think like: I’ve failed! I’ll never be able to do this! Why is it impossible for me? I must be different, everyone except me can have LD’s! This is so disappointing! 
Think positive! There is no, absolutely no reason to believe that you are not able to get LD’s when everyone else can! This should be your motivation: If they can do it, I can, too! Set yourself goals, reasonable ones, like to have an awesome DR and vivid dreams, like practicing LL and RC’s and so on. Keep track of those goals and enjoy what you’ve already done, what you experience!
You don’t want to force yourself to have LD’s, this won’t work. Stress is the killer of dreams and sleep. Don’t punish or frustrate yourself by negative thoughts. Dreaming is something enjoyable, that’s why you are here, right? No? You are here because you want LD’s? Well, but LD’s are dreams! Enjoy your dreams, enjoy those moments where you wondered about some DS, where you almost did a RC, where you had a FLD and flied. This is the spirit you want to have!
Motivation, confidence and practice. These are the keys. So, don’t give up. You WILL have your first LD eventually! 
Well, give us some information with which to help you. How frequently and how detailed do you remember your non-lucid dreams? What do you do during the day to promote lucid dreams? What do you do as you go to bed to induce lucid dreams? What do you want to do while lucid?
You might even think of some things you can do to help yourself while answering that, and the forum’s members can help you better if we know what you’ve been trying.
You might have already had lucid dreams but forgotten them; that’s why it is so important to train your dream recall.
Oh it’s very possible, man. Perhaps what is keeping you from doing it is the fact your subconscious believes it’s not possible. I recommend using EFT and or subliminal messages to remedy this.
what is EFT?
I feel you man, I’ve been interested in LD for years, have tried for months. Never had any success. Few days ago, out of the blue, I just happened to have 2 LD in the same night… Each less than 5 seconds long, but still… That motivated me very hard to continue…
I really didn’t wanted to keep a DJ… But when experimenting with sleep patterns, I realized how important it is. For me, to remember my dream I have to try to remember in a very specific way; just like when you realize you can control a muscle you didn’t know you could control specifically.
From what I recall of my really short LD, some things seems to help me:
- always keep a mental “trail” of where I’m coming from (what was I doing?)
- always keep doing RC: “Is this situation plausible to happen in my life?” If not, I need to augment my awareness.
- always sleep at least 7 hours.
- No alcohol
- I’m a night owl, but to remember dreams (and have LD), I need to fell asleep before 11 pm. This way I have very intense, vivid dreams, that eventually wake me up at ~5AM before I fall back to sleep. It’s at that point (5AM) that I remember my dream… And I need to note them right away in my DJ.
It stands for Emotional Freedom Technique. It can be used to completely modify or overwrite any thoughts that are on a subconscious level. In my experience it is WAY more effective than hypnosis and subliminal messaging combined. It’s unbelievable what it can do, albeit it may seem strange to practice at first. It’s definitely worth googling.