Surround yourself with all things electronics:
Books:
Read up on electronics online:
Join hobby electronics discussion forums:
Find good sources of electronics parts and components and start hoarding!
I like to use:
- Amazon
- Jameco
- MCM Electronics
- Maker Shed
- Lightake (ships from China and takes longer, but prices are great and shipping is super cheap – like, 0.20 or so per item, varies with size and weight)
- Adafruit
- SparkFun
- eBay
- Local flea markets, swap meets, garage sales, etc.