A Few Things to Remember When Rendering Tracks

Rendering your sounds as you go is incredibly important. Not only does it free up your CPU when playing back multiple tracks, but it also allows you to visually scan the track waveforms for any issues and reduce the final mixdown rendering time. The thing is, when you render each individual track there are a number of things to look out for to maximise the quality of your track.

Don't Go in the Red

Yes, it's simple. Yes we all know this. But look at your last DAW session, I can make a pretty good bet that when you were at the instrumentation stage, several red lights flashed on your screen. We all do it and as long as you reduce the volume below 0dB before rendering, you'll be fine.

If you fail to do this and render while it its clipping, you've just ruined your sound and there is nothing that can be done short of re-rendering at a lower volume. 

Before Rendering tracks, I usually select all tracks and turn them down by the same amount. Then when I render them, they can just be turned back up, safely knowing the audio quality is intact.

Plugin Quality Settings

Sure, not all plugins have quality settings, and many are CPU friendly, but there are also many outwith this category. Consider NI's Massive, it is huge, that's why they have settings from eco to ultra. 

When you are composing and arranging, it's pointless having your plugins on the highest quality settings unless your computer can handle it. At this stage, your focus is more on the direction of the music anyway so the tiniest of audio quality difference is not a problem. 

When you render it though, it's best to bump the quality up to max. As with before, once rendered, you can't make it better or fix an issue so make sure you have the highest quality audio to work with.

Have a Folder At the Bottom of Your Project

Use it for the old MIDI stem tracks. Basically, you don't ever want to delete the original sources of the sound. As rendering makes any prior edit irreversible, you always want some sort of back up. I do this simple by muting the originals and leaving them in a folder at the bottom of the project.

All the rendered and muted files are dragged to the bottom of the 
project in case they are needed. Good for remixers.

Consider Your Sends and Receives 

If you have a kick drum track that is sending to a pad triggering a side-chain, make sure that by rendering the kick, you aren't removing the side-chain.

In Reaper this isn't an issue because any track with a send will transfer that send when rendered, as in, the rendered track then adopts the send.

Make sure your DAW allows this, otherwise you may need to order rendering stems so that they are not affected.