On mic selection, omni vs uni is not the only consideration. You also need to decide between dynamic and condenser mics. The former doesn't require power, the latter does. Condenser mics will typically have hotter outputs than dynamics.
You should also test out mics if you can so you can match the mic to the qualities of your voice. I switched from a mic that picked up too much of my low end to one that responds better to my mids and mid-his.
Pay attention also to mic technique. Talking straight into a mic on axis increases the possibility of plosives. Try talking across the mic slightly off-axis to mitigate plosives. Pop filters alone won't necessarily do the job by themselves.
When it comes to metering, the new standard is LUFS (loudness unit full scale). This method is better at accurately representing the loudness of sounds as actually heard by our ears. Most modern DAWs come with LUFS meters but you can also get one as a plug-in. Settling on a certain LUFS level (like -18 or -16) will help ensure your recordings are consistent.
For those of you recording in less than optimum spaces, try a plug-in called Deverb. It does a pretty good job of removing the echo of untreated rooms.