Hey kids! Proud dummy and toy here. I wanted to share with y'all how I went about designing and my own wavy border stickers by hand! Doing this yourself rather than buying or racking them means you can save money/risk, customise the colours or design, color match the border, and work in any size you want!

Here's the sticker (actually drawn on the back of an index card, because that's what I had on hand):

And below I'm gonna dissect this gude, so it's easier to follow.

The BLUE lines on the outside are the furthest to the edge of the paper that the border goes.

The RED lines on the inside are the furthest towards the centre of the paper the border goes

The GREEN lines at the corners are the points where the "waves" start and stop, if we ignore the curved corners (which you'll want to add later, after the waves). These are just continuations of the outer BLUE lines, but I wanted to point them out.

the PINK dots are the sorta "peaks" going outwards to the edge of the page. I drew humps between these and the green lines.


So, to go step by step:
1) measure and draw the outer lines, to decide how far in the border will reach.

In my case, I drew it in by half a centimetre on all sides, as a rule, I'd keep these uniform to the opposite end (which is to say, both long ends are the same distance in, and both short ends are the same distance in) but as always, you're free to play around and experiment.​

2) measure and draw the inner lines, to decide how big the waves are.

In my case, I drew these another half centimeter in from the outer lines, but by no means do both lines have to be the same distance. Again, I'd keep opposite ends uniform unless going out of my way to do something funky.​

3) Measure out the points to draw the waves between

A normal wavy border sticker has two points (or three waves) along the longer edges, and one point (or two waves) along the shorter edges. So in my case I measured 1.5 inches from either side to place the dots at the long edge (the middle wave is slightly smaller), and measured halfway through the page for the smaller sides. Waves don't have to be uniform, but as a rule should work out symmetrically along both axes.​

4) Draw the waves between each point and green line.

If you're not comfertable drawing lines with precision like this, I totally understand. Work in pencil, take your time, and draw dotted lines. Use the dots and lines there to help guide you, but do what you can! If you want to play with the shape of these waves (like making them melty, or sharp) I'd draw them normally first, then use those lines as a new guide.​

5) draw in the rounded corners from the ends of the green lines, inside the outside guide

These will be a lot easier to draw then the waves, because they have less distance to travel, and more guidance along the way.​

6) finished!

Just draw or paint overtop, following the lines you just drew! If you want to avoid doing this all the time, consider making a stencil, then you can just trace, spray, or screenprint along the stencil and quickly have a sticker made!
​

​

Mine's admittedly a lil' rough because I was impatient and exhausted after work, but I want to see what y'all can come up with! Color combinations with the border and fill, multiple colours, weird sizes... Go nuts and have fun!