Well my friend, volume is the level. So you may want to work with compressing the dynamic range. This can be applied to any audio, but the suggestions are primarily for voice.
I am not in front of my system so this is from visual memory. Somewhere in audio effects you'll find "Dynamics".
Drop this onto your audio clip and get into the effects panel. You find an "edit" or "custom" button that will open it up. In addition to presets in the dropdown menu, you can customize your settings and save them for easy retrieval.
For voice, I'll EQ some (low cut if it needs it, and bump it up a bit to the 2.5-4kHz range). I'll also compress and limit it. Compression pulls the quiet parts up. Limiting holds the top down. So you end up with a voice (or other source) with less (or almost none, if you are rough with it) dynamic range. The clip seems "louder" without a volume shift.
You're just reducing the difference from loudest to softest parts and, in the case of the EQ settings, working to improve intelligibility. When folks don't have to work as hard to hear everything said, the volume seems better, without being louder.
Dell Precision T7600 (x2)
Win 7 64-bit
Adobe CC 2015.02 (as of 6/2016)
256GB SSD system drive
4 internal media drives RAID 5
Typically cutting short form from HD MP4 and P2 MXF.