I've been using Rx for a couple of years now and it does take a good bit of practice.
Don't be afraid to adjust the display. Being able to clearly make out what doesn't belong is a lot of the battle. Also, zoom should be in just about constant use.
For the spectral repair modules, the before/after and surrounding region settings are key. And don't just trial and error those adjustments. Look at what's going to be used for filling in the hole that "replace" will create and think about what it will sound like when it's in there.
You can also use the spectral repair modules on a single channel. If you're having a tough time removing something, it's almost always louder on the right or left side. Try using the "remove or pattern" modules on the loud side and "attenuation on the soft. It does take patience to do things like remove entire conversations since that's best done syllable by syllable but it can be done seamlessly. I always try using the "replace" module first but you need to adjust the "before/after" carefully. Sometimes it's better to remove slightly louder sounds (like whoopers) by attenuating it a few dB first, then trying replace or pattern.
Short loud noises like coughs are actually pretty easy. If I'm the one coughing (with head mounted mics) the sound pretty much covers the entire spectrum so using "pattern" on the entire slice with the "time" selection tool is pretty effective If the cough is from someone further away, you can use "replace" with the "time/frequency" selection tool and do it in one frequency block at a time.
The "partials" module works great for things like the klink of something dropping on a metal chair. If it's a concert with metal chairs, be sure and save that as a preset since the sound is almost identical every time.
I guess I'm assuming that you already have a handle on the different selection tools. If not, you need to practice how much you need to zoom in , which selection tool to use and making a selection box around the offending sound. Sometimes a single box just won't do it (you end up removing too much) so a series of selections works better ( I've asked them to integrate a lasso tool like Audition has and they said they'd put it on the list). They have upgraded the selection tool so when you make a box around the sound, switch to "listen to selection only" or whatever it's called and if you haven't quite gotten it, you can move the borders of the selection around till you do.
Once you think you have the selection correct, apply whatever module you've selected then listen to just the selection. Many times if you've done something wrong in the adjustments or just plain picked the wrong tool, you'll know right away. It should sound like the surrounding area.
Then back up the playback head and listen to a second before and after of the entire region. If that sounds like it's pretty well blended in, back up even more and see if it still makes sense. Be sure that it's all good before moving on. You can go back and "undo" the repair but it's never quite the same I don't think.
Sometimes it's important to do a little planning to do some of these impulse repairs using the Spectral Repairs with "before/after weighting controls". For instance, it someone sneezes a few times in quick succession, you need to start by repairing the right one first. Say, if their sneezing fit started just as a change in the density of the overall music and stopped while this same density was continuing, you'd start with the last sneeze first and the "weighting" would be totally "after" the sneeze. That way, you can do the next one the same way and even if the 'interpolation" used the spot where the last sneeze was, it ain't there anymore (I can't tell you how many times I've remved one offensive noise only to have the interpolation software replace it with it's brother from half a second before or after). Then you just work your way back till they're all gone.
One major tip is if you're recording in a venue that has something like the ventilation system or some other steady state noise, get in there before there's lots of other sounds and try and capture 10 seconds of just that noise. If you can you can splice it onto the front of each of the tracks with that noise on it and "teach" the Denoiser with that. Otherwise you'll be forced to try and find a long enough section of your recording to "teach" the module what it is that you want it to remove. Sometimes the "Auto" setting (or whatever it's called) does a pretty decent job (but that's up to lady luck).
With the Denoiser, you don't have to use all the settings so if there isn't any tonal noise, be sure and uncheck the link with broadband noise. Also, learn to use the "Output noise only" (or whatever it's called). Some of those preview type features can be pretty damn slow but after you use them for a while, you won't need them as often.
Sometimes things start to get sluggish and you just can't seem to find the noise in the spectragram. Sometimes it's just fatigue but sometimes you've just totally filled up your physical memory with "undo's". Don't let this happen! I keep an open Activity Monitor in my dock to keep an eye on this. Once that pie chart gets much more than half way full, I go back and double check how the repairs I've already done sound and SAVE!!! Then quit Rx.
If you have a memory clearing utility, use that before reopening Rx. If you don't, restart your computer to totally clear that memory. Time really flies when I'm using this stuff (especially if everything's working like magic) so all of the sudden I'll check the log and I've made a hundred edits. If Rx were to freeze when you go to save this,.. big bummer!
And speaking of magic. Sometimes you just get on a roll. And for some reason or another, each repair can be done without any adjustments. Like I said,.. magic! When that happens, save those settings with a descriptive name. Sometimes when you're stuck, running through those settings can make all the difference.
Well, I know I'm forgetting a million things but it's been a while since I cranked Rx up so sue me. I've go a big log of projects to do now so if I come up with any goodies, I post them here.