If you're not already, wear a hat. Keeping your head warm will help keep your hands & feet warm. Hands sweat a lot, especially if you're working with them, and wicking glove liners will get the moisture away from your skin. Make sure that your wrists are covered, the blood vessels are close to the skin and radiate heat away. I'd recommend a multi-layered approach, with the wicking liners first, then an insulating layer (wool is my favorite), and finally a breathable, waterproof outer layer with or without insulation. Remove 1 or more layers as temperature and conditions allow. Make sure to bring the other layers with you when you buy new stuff, so you can verify they all fit together. Don't wear them too tight, you shouldn't feel any restriction or pressure anywhere except a slight amount where there's elastic or straps.