Play with the different software packages until you find one that ‘clicks’ for you. That makes sense to you and you will remember how to use when you come back to it a week later.
Each has their own personality and one may be better for the type of work you hope to design.
I want to create organic forms so I have been working with Rhino a lot.
Watch the Tutorial Videos
Watch the tutorial videos for the software you are trying to learn. Work along with the video if you have the software.
But also watch videos for software you don’t have.
I learned about vase mode by reading a post on mastersketchup.com . He does an excellent job of explaining the process in Sketchup which can be applied in other software.
For fun I did Autodesk 123D – Minion Tutorial by Saturday Kids Have More Fun.
Explore the Internet
When you find a piece you like, think about how you might design or modify it. What software did the designer use? What printer settings?
Print the design if you have a printer.
Buy designs so you can print them. Most designs are relatively inexpensive when you consider the amount of time the designer spent doing the work. Plus I’ve learned a lot from printing other peoples’ designs.
I bought a design from Dizingof early in my process. It was inspiring to see the print come to life on my printer. Well worth the money.
Have fun with learning and creating. Being able to design and print a 3d model is amazing! It’s a real high without the drugs.