Start by bleeding new fluid down to all of your brake calipers. You can get one man brake bleed kits from your auto parts store. The kit is comprised of a tube with a spring loaded ball bearing check valve at the end. Cheap & easy to do yourself. About the only other tools you will need is your tire changing stuff & a brake line wrench for the bleed nipples.
Brake fluid has a tendency to absorb water/moisture so I flush my brake system & bleed my brakes every 1 or 2 years. I have NEVER had a brake problem or failure.
