You can do normal drawings then scan them and size to fit the hoop size you want! Good Luck

Or take a foto and load it to your software (embird?)

I usually draw the oldfashioned way with pencil and paper and scan it, or use pictures I've taken, or scan leaves etc.
Depending on the size of the final design and how convoluted the lines are I choose a stitch length of 2 - 2.5 mm.

Same as the other gals here, draw & scan. I have however sometimes just drawn right on the screen with the mouse. If you can make a rough outline with your mouse, you can fine tune it moving the stitch nodes around. You can make some neat shapes just free handing like that....

If you are looking for a tablet to use with digitizing software, I hear the Wacom Bamboo tablet is really good...it hooks up to your computer and you draw with a stylis pen instead of your mouse...it's really pretty cool. You can put a picture, outline, etc under a clear flap and trace over a design as well...hope this helps! Don't have the link but if you Google Wacom you can get to the site easily.