Digidesign (makers of Pro Tools software) published an extended special on recording vocals in 2004. The series focuses on using Pro Tools to produce polished vocal tracks, but 2 of the articles deal with plugin effects, and the techniques are much more generally applicable. You can use the advice from these articles with any DAW or recording platform, even without the specific plugins described.
The first article Adding Effects to Vocal Tracks looks at compression and gating to clean up the vocal sound, with a good overview of various approaches to reverb.
Gates allow an audio signal to pass through them if the signal is above a specified threshold. When the signal is below the threshold, the gate closes, attenuating the signal partially or fully. Gates are utilized to allow the desired (louder) signal to pass through to the output while denying unwanted (softer) signals. They’re useful for eliminating unwanted noise on tracks (like headphone bleed or even the singer’s breathing), for creating cool effects like cutting off reverb tails, and many other applications.
The next article, Adding Ambient Effects to Vocal Tracks, delves more deeply into the use of reverb, delay, and chorus to add depth and character.
Putting your delay effects in stereo can really make your mixes sound wide and deep. You can pan your source track to one side and a delayed signal to the other side. Or you can put the source in the middle and pan delayed copies of the source to each side. For this to be effective, select different delay times for each side of the stereo field. A good technique for thickening a vocal part is tripling the original track by using single delays panned left and right with delay times of 16 ms and 32 ms