Yesterday I thought: "What do I want to do in Blender?". And suddenly I realized that I did not know, because I have a million ideas, but nothing definite. And at that moment I realized how important sketches are, because they allow to organize thoughts, and free your head of it. I always thought that the concept art and sketches are not necessary. Now I understand that without them it's impossible to start modeling, you do not know where to start.
Of course at the moment I can only make a glass in the Blender and nothing more difficult, but I imagined for a second that if I could do everything there.
Now I will draw my ideas regularly, I'm not good at drawing, but this will allow to accumulate experience and ideas for modeling, and it's possible to see how to draw better.
I will put sketches in this topic.
I think that I will start with something like this, in Blender.
Not bad, not bad. I like the Gundam/mech head. Would like to see it with colors, but that's down the road, and that's okay. Take a look at the Color Course when you get there.
Is the middle thing a knife/weapon? Interesting design. Depending on what you're designing it for, maybe the "finger holes" could be more rounded, if it's for the comfort of a person, or even a little bit of tolerance for something mechanical so the stress is less.
Can't really tell what the ring thing is, and looks like maybe another weapon. It looks cool, but have you thought about possible functionality? It might help to make it look a little more believable, a little more grounded in reality, but that's up to you.
Your.... fireplace/door thingy looks pretty neat, but it's suffering from bad perspective. Take a look at the Intro to 2D Perspective Course when you get a chance. It's a bit dry, but there is a lot of useful information in there. Perspective governs our world whether you realize it or not, so get lots of practice with 1 point, 2 point, and maybe a little of 3 point perspective, too. The more you use it, the better of a "feel" you get for perspective when you're freehanding something. There's also Perspective Made Easy by Ernest R. Norling, which is a very good and concise manual on perspective.
You've taken the first step, but there's plenty more to go. That's okay; take it little by little. It's about gradual improvement, not a sprint.