If you're going to run missions, make your ship as fast as possible. Don't carry any weapons. The Sidewinder is a sitting duck with it's standard E-class thrusters and power distributor. They're OK for farming bounties in a high Resource extraction site because the pirates won't shoot at you if you do it right, but for missions you need A-class PP and PD to get away from the interdictors. Never fight the interdiction. Always have 4 pips to engines and 2 to shields when you're travelling. When an NPC tries to interdict you, submit (zero throttle), boost, boost and engage your FSD, then wave the interdictor goodbye. This is the safest, most reliable and most efficient strategy. If you can't make your ship fast enough, use a heatsink launcher. The moment you drop out of supercruise, drop a heatsink, then boost. The heatsink will break target lock, which buys enough time to get clear. If your ship has a boost speed over 300m/s, you won't need heatsinks.