Before actually building:
- Have a rough idea in mind of what you want to make
- Have a building style in mind
- Make a color palette: It's important that the colors go well together
- Make an overview of what you need. Simply write a list of things, such as 'custom terrain', 'outlining', 'rough size', 'help from others', 'deadline'.
The actual building:
- Make a rough outline of your build. Smartest is to do this with wool, and a color that is not involved in your building.
- Get the custom terrain done. When you use programs such as worldpainter do this before building. When it comes to plugins/mods such as worldedit, do it after you made the outline and before you made your building(s). However, you should wait with placing trees.
- Start building. Pick a place to start, such as the entrance. This is important, since the first blocks you place will define the entire size of your building. Also, you can build relatively 'flat' and undetailed when it comes to this.
- Slowly start detailing. As soon as the building is making (flat) progress, start adding details. Do this by switching up blocks, adding depth, changing some shapes more to your liking, etc. This step takes the most time, and your skills will increase only by practising. (Find your style!)
- Continue the 2 steps above until your entire building is done.
- Check if the building is to your liking.
- Start detailing the landscape. Do this by adding trees, wheat, leaves, rivers, a pond, etc.
After building:
- Check your building, check the landscape. Do you like the final result, or are there things you want to change. Doubtfull? It doesn't hurt to change something! If the change is worse, simply change it back. Trying won't hurt you or the building!
- Take screenshots, images, etc. (I guess you want to post it to PMC or something, so lets do these steps as well)
- Upload your project.
I could write it million times more detailed, but this is the simpliest yet most advanced version tutorial I could think of. Peace