FinalPlug is a professional peak limiter/volume maximizer with extensive bit depth truncation and dither options, making it ideally suited for a final mix. Its interface could hardly be simpler. Select a desired output ceiling level, say -0.1 dB, and then adjust the threshold level. As you decrease the threshold you increase the volume.
The peak limiter section works by looking ahead 1.5 milliseconds. FinalPlug’s great auto-release feature analyzes the input signal to determine peakiness, and selects the optimum release time for the program material.