I am new at 3D printing too. I have been modeling with a Blender for a couple of months but all that I have been doing to reach my goal is :
1) search tutorials how to model with a software that u want ( Google, Youtube, Vimeo..other experience)
2) try to model simple things
3) download other creators work and open it with software that u are working with and analyze them to understand how other create it .
4) get a good understanding about 3D printing specifics (it is not so simple as it looks at first glance, but when u got the idea it flows fluently)
5) try to send your model for an experts on 3D printing and get advice from them
6) try to prepare your model for 3D printing and see what you get
Good luck !