In light of @motsu ‘s comment on feeling like his sculpt is a failure, I want to share an experience I had about 3 years ago.
Right after Leonard Nimoy passed away almost 3 years ago, I decided that I wanted to do a tribute sculpt. I wasn’t aiming for a completely “realistic” version, but was also wanting to practice caricature. I found several references that worked from.
After just a few days, I had my first “version” — and it looked NOTHING like him:

It’s rough, crude… It looks kind of human. But I could have called this a failure and stopped here. But I didn’t. I kept going. Kept refining. Kept comparing what I had from different angles to the references that I had pulled up. I kept pushing the sculpt further. Not in hours. Not in days. It took me weeks. Over most an entire month. After many hours of work, I eventually got him looking decent enough that people were recognizing not only the character, but also which actor’s version of the character.
https://cgcookie.com/u/gradyp/projects/spock-leonard-nimoy-tribute
If I hadn’t kept going, I would never have realized the eventual outcome, which is still, 3 years later, one of my proudest accomplishments and most favorite pieces on my hard drive.
So if it looks like crap after just a couple of hours, that’s okay. Keep working on it. Keep pushing. Keep trying. If it takes a month or two, that’s fine. You don’t have to create a masterpiece in a single day. In fact, several of the artists that I watch on Twitch will spend several streams, 4 to 6 hours at a time, on a single character, working for a week or more just on one character. Does it matter if it takes you 80 hours to do it if it turns out great? I’d be willing to bet that most of the best pieces you see online took at least 40-80 hours to get there. You can do it, if you just give yourself a chance!