Hi there !
You should start with simple projects. Think about something you'd like to try. How about a small PCB board that has flashing LEDs ? Interfaced through a pareller port, perhaps ? When this works, you could try upgrading it to interface through a USB port, for example, to increase the complexity without doing radical changes. Put your software skills to work and write a device driver for the USB version ?
Another fine example of a simple embedded design is a measurement or control of somekind. How about coding a remote control unit, that's plugged to your PC and can control your TV ? Or how about an audio device ? Take your home CD-player, build an audio digitizer board (a simple ADC IC is enough), plug in the stereo cord from the CD-player and have your PC read it through USB, for example.
All these can be considered 'toys'. They start simple, but offer a large variety and lots of challenges. Also, by doing small 'upgrade' changes, you can practise more and still keep a good basis of the original work.
-Antti Keskinen