Mixing vocals can be approached in many different ways. It really comes down to what you're looking for, or what the artist is looking for as in sound. But typically the lead vocal would be centered. Now, for something like a hook/chorus, or for more powerful sounds most artists prefer (even myself) to stack their vocals which then you'd still keep the lead vocal centered but you'd pan the other 2, 4, 6 (however many you need to get the sound you're looking for) and pan them all differently. Let's say you triple stacked a vocal... You'd center the main, hard pan (around 70-90%) left the first stack and hard pan the third the same except to the right. If you added 2 more stacks you'd want to pan each L-R around 50-60%. Each would also need to be EQ'd and compressed differently as well to differentiate them from eachother and you'd use the fader and drop or add dB's to make it blend together, but stacking easily causes clipping so you'd most likely be reducing the dB's of the stacks. Another good technique for differentiating the stacks is to pitch shift them but very lightly, like 6 cents to the left and -6 to the right. For vocals you really need to know a lot about FX chaining, aux buses, inserts, etc.
Now for reverb. Reverb is done through a aux bus and not an insert. If you're not familiar with aux buses, an aux bus is where you send tracks and the aux would be the receive meaning when you solo an aux bus any tracks sent to that bus would be played as well. But basically you'd add an ambience vst to the bus insert and mess around with the decay, spacing, delay, EQ filtering, etc until you get the ambience sound you're looking for. You'd then apply a multi band EQ and filter out what you feel doesn't belong, then you'd either apply compression to it til it grabs the reverb or you can apply a multi band compressor and not worry about doing the multi band EQ and compression separately. Multi compressor is more intricate tho since you'd have to make the attack, release, ratio, threshold, knee, etc different for the low, mid, and highs. Then you'd use the fader to blend it in with the rest of the music, this is why you need it sent through a bus rather than an insert.
sorry it's really long but it's really hard to explain without going into detail. That's just the tip of the iceberg too. I didn't even get into automating, de-essing, and FX chaining.