Your way of create levels

[Matt_The_Slime]

Usually, most of my levels start like this
-I hear a piece of music
-Take that music, put it into level
-Find fitting graphics
-Make it fun!

[Thehelmetguy1]

1: First of all, add custom graphics, so the level looks better than it actually is
2: Spam slopes through the level
3: Put a boom boom as a boss
4: Spam rinkas
5: Add touhou music
6: Results!

Now seriously, this is the way I am sticking to(It is rather new though):
1: Come up with a setting and a gimmick(If there is one)
2: Prepare custom gfx and music
3: Draw the structure of the level on paper
4: Build the structure in the editor, with layers, events.
5: Add enemies and items
6: Test, and fix any issue found

[Oshi]

For me the most feasible ways to create a level:

Is to be inspired
Take notes of what you want
Sometimes I grab a grid notebook and I start to draw sketches of my idea
for the level would be or simply make traces that will go as an idea of my final result
I look for or create the graphics needed for the level and atmosphere of this. I think an appropriate
name for the level, I check the bugs and errors.
Everything you have thought put it on the level do not stay with the desire to decorate something.

And good design my ideas in SMBX Level Creator

ITS FINE

Wow no need to be rude like that

[8lue Storm]

Wow no need to be rude like that

I know right :(

[TheNewGuy]

Wow no need to be rude like that

I know right

But that post was useless.
At least I didn't report it.
Yeah,this is getting off-topic.

[Super Luigi!]

I usually think of an idea I want, gather/create any required custom graphics, and begin building the level.

[John The White Yoshi]

Wow no need to be rude like that

I know right

Welcome to the forums. It's what some know this place for.
It's a bit upsetting, I know.

When it has come for me to design levels, I focus the gfx and style of level to fit the theme I'm trying to go for. Music is the next thing I worry about. Music and sound can make or break a level's quality, especially depending if the music doesn't the theme of the stage or tone. An example of unfitting music for a calm, somewhat flatish SMB1 level that's light on enemies and more heavy on the platforming near the beach, would be the Partners In Time "Panic!" theme. A fitting piece would the NSMB Beach Overworld music (So good and relaxing, yet bouncy and happy).
Finally, I work on designing the level. The design of my levels have a mix between the open multi-levelness of SMB3, the ceilings of ground like an overpass or caveness piece like in Kirby, with the optional hidden goodie paths like in the New Super Mario Bros series. And yes, that does mean my levels tend to more linear than what people would like, but I honestly rather have my episode FEEL like a retro Mario game, not just or only look like one.

[Enjl]

It's important to remember that the Super Mario series has made massive advancements in terms of level and game design over the years, so something meant to feel retro can easily feel dated.

Also since when do people not like linear levels? Nonlinear levels get so much more flak for just being horribly executed most of the time.

[Marina]

I think the "levels need to be non-linear" discourse on SMBX has long passed. Moment-to-moment non-linearity in linear levels is where it's at now, yo.

[Taycamgame]

Here's how i design levels:
1. Gather the resources you need. This includes Graphics, Music and possibly lunalua APIs.
1.5. Create any other graphics or lunalua code you think your level will require, if you couldn't find them pre-made.
2. Place some blocks down for the start of the level. At this point i usually know what i sort of want, but if not:
2.5. Design the layout on paper. (this doesn't have to be physical paper; it can be on your computer!) This helps with the structure of the level, and you can see how the level could look like before making the whole thing. This way you can check to see if things will fit in place.
3. Come up with the theme of the level. Will there be special gimmicks? Will your level be purely platforming? Will there be a storyline?
4. Create the layout of the level; this includes placing blocks, NPCs and your chosen gimmicks.
4.5. While creating the level, remember to spice it up a bit by playing around with setups for the gimmick as well as the structure of the level. It should get progressively harder towards the end.
5. Test your level. Then, if there is something broken, fix it. If it's not broken, make it better!
6. Make adjustments to the level, test and repeat until you are satisfied with what you have.
7. Place decorations down; this includes BGOs and Coins, aswell as ? blocks. Think of a good place to put your powerups!
8. Make one last test. If you are happy with what you have, then you can call your level complete.

In terms of an episode:
Make sure the levels flow from one to another. So for example if you are making a grassland world, make it so level 1 is in the field, then it goes to the forest, then the boss is in a Castle on the Hill.
Make sure the levels get harder further on. If world 1-1 is harder than the final boss then you need to change it.
Sometimes it is ideal to make it so a whole world revolves around a specific theme. For example a beach world should revolve around the player needing to dive in water.

I hope i helped!