Finaly submited the final version you can see the link on the bottom!!!

1. Drawed and painted on photoshop for the last 3 weeks, 1/2hours every day with a tablet and mouse (I use my both hands Ehehe the left one with the digital pen and the right one with the mouse for the basic tools, like changing colors and brush sizes). Ehehe right handed cant do this!lol
The original size is 3000x7460. It's much easier if you start the drawing with a big background because you can always reduse it and the little details are much easier do draw.

2. Started the drawing with a medium size brush, has you can see on the 1st 4 drawings. I already had an idea of what I was going to do, so I just did a quick sketch of the animals without big detail.

3. After the quit sketch came the hard part. I never drawed something so big so I didnt even no were to start!lol But has you can see I started with the background. Preety strange because I always block with the backgrounds.

4. Next came the animals... I did the same thing to all of them so I'll use the leopards heads that I saved more often to expain how I painted them.
First with a white brush I erased all the unecessary lines of the sketch and gave it the real head form. Next I corrected his eye and and started giving him the color basic colors of his skin. After that came his dots and a correction of his ear. I did all of this in the same layer. Actualy I didnt even use more then 3 layers in all of the drawing. They kinda confuse me so I prefer not to use them. well were was I?! yes the dots... After all of the dots came the little details like his fur and wiskers. with a white one size brush and 200% view I gave him does little ditais. Well finaly after all of that I usually used the burn or dodge tool to do the little skin shadows and shiny areas. Well thats basically what I did to all of them. It sound easy but it actually takes some time, pacience and lots of music to do it

5. Well after painting some animals I didnt like those clouds I did near the moon, so I dicided to erase them and did a little experiance trying to do imitate space. Thats when I used the other two layers, just to see if it looked good. I also used the color balance to change the color of the experience has you can see. So after that I liked it and started to do the stars. Just one click with the mouse and diferent brush sizes to do them. with the pen I did those purple blue effects and the big stars.
In the end I realised something that you'll only understand when I submit the final drawing and explain the swiling of the star over the moon! To do that I used the liquify effect.

6. Next comes the sea... I'm not really satisfied with it yet so the final one will have some diferences. I used a little brush to do the bubbles and a big brush to do those lights that come from above. The whale was done preety much the same has the other animals. Only the little yellow fish was almost pixel art!lol And I think his to big. But If I did him a little smaller he wouldnt even be noteced.

7. I'm steel working on the last details, but I hope you liked the tutorial and will see the final drawing The rest you can just watch carefully each image and if you have any questions on how I did something I'll be glad to help and I hope you like each animals head I add next to the leopards
One more thing sorry about my english!lol I must have milions of erros!lol

you can see the final version here [link]