I too like to think I can predict the weather, but I don't use anything but my eyes, ears, and bones. I'll look at the radar and weather maps from time to time, but I find the best way to predict the weather is to pay attention to the clouds, the wind, and the sun. For example, we've all seen "herring" clouds, those patterns of clouds that kinda bunch together and, if looked at properly, look like a herring's body. These clouds, depending on how closely bunched together they are, tell me that there's going to be wind and rain within the next 18-36 hours (tighter together means sooner than later, and probably more intensity of rain.)
Another way to get a good weather indicator is to watch what the birds do. When you see seagulls circling very high above, you can be sure you're in for some wind within 24 hours. The higher they circle, the higher the wind speed will be.
Alot of this I learned from back in the day in Boy Scouts, some more from commercial fishing, and even more so from family members who have relied on weather before there was decent (hehehe) weather organizations to predict weather. If I was to rely on any one device for predicting the weather, I'd go with a barometer. Changes in air pressure are deffinate indicators of what the weather will be in the next few hours, but not so good for a long term prediction.