Not enough time.

So I woke up at about 6 am today and tried for a FILD. I didn't get any SP or anything like that. I think I was in a normal dream after that because I passed out. In that dream I noticed that my left hand had a pretty big scar on it and I'm pretty sure that told me I was dreaming. I then went to look around for stuff to do, and I got the feeling like I don't have much time left, and I really felt my heartbeat. It was day time when I started the dream but the sun was going down and it ended mildly dark. Then I woke up from the dream. Will focusing more on my environment next time help to prolong it?

Maybe, maybe not. Do you usually wake up at 6:00? Sometimes it's hard to dream after usual wake time.

Darkness will end my lucid dreams many times. Try turning on a light! Easier said than done. Dreams can fade fast.

Here's a suggestion: Don't think about waking up, don't fear waking up. Banish these thought from your mind. If you think "please don't wake up," your brain will register "wake up," "please," and then "don't." Of course, by then the waking sequence will already happen. Instead, focus your entire thought on your surroundings and dream. The best success is achieved when you remember what has happened in your dream until that point. It tends to keep the mind active on it, and even if you end up waking up, you will be rewarded with strong dream recall (as opposed to only remembering "aw crap! The dream is ending!").