Settings varies from one UTAU to another so it's up to you to discover the potential of a voicebank!
1) You need UTAU (obviously), a voicebank you like to use and Audacity for this to work. My tuning heavily revolves around flags and minor editing in Audacity
2)You have to add this really, really long flag combination in the Project>Project Property>Rendering Options
^I said it was long. And not just long but really confusing. Here's what it means(you'll be learning basically half of the flags there is out there):
-F1 = F flags cancels any nasally sounds.
1 is the only number that can cancel nasally sounds or else you'll be doing the opposite (depends on flag combinations)
-Y50 = Y flags makes a voice sound clearer with clarity. The bigger the number is, the clearer is sounds and vice versa
-BRE0 = BRE0 flags is the breathiness in the voice.
-t2 = t flags adjust the pitch in 10 cents (1/10th of semitone) units
-F5 = This F flag is paired with F1 to cancel the nasally sound further more. By its own it adds nasal sounds.
-B0 = B flags works similar to BRE flags. People say it works differently like a "gravel-y voice" or a "raspiness" but both effects the breathiness of the voice.
-H0 = H flags makes the voice sound muffled.
-x25 = x flags affects the clearness of the voice according to the distance from the recording note (higher: clearer; lower: muffled)
-c99 = Apparently x flags normalises all notes to the loudest volume possible but I'm not sure. There's a capital C that gives clarity so maybe that's what it's for?
-g-2 = g flags are gender flags that change the femininity and masculinity of the original voice (+g = masculine, -g = feminine)
Okay we need to stop =_=;
3) After that, select all notes and right click. Press "Property" and set the following:
-Preutterance; Overlap: Clear (do not insert anything because oto.ini will help you unless you want to change an individual note)
-Consonant Velocity (beta): 100 - 140 (Hasami, my utau, especially needs 140 because she has long consonants such as 's', 'ch' etc. If you don't have very long consonants, do the opposite [go below 100] if it sounds just about right, leave it alone)
-BRE: (don't put anything there because sometimes it doesn't sound good eg my UTAU doesn't good on BRE: 0 because she has a soft voice and it can mess up the voice sometimes)
-Flags: F1F10 (you can change the number on the second F flag as long as you have the F1)
The rest leave default.
4) Select all notes and click on the five buttons on the top right hand corner with lines that looks like wave lengths.
Press Reset, followed up by P2P3 button then lastly the ACPT button. What this does is it connects notes according to the oto.ini (as long as you don't have anything in the Preutterance and Overlap option)
Then, render to any folder.
5) Open Audacity and import karaoke and vocals. Align the vocals accordingly to the karaoke.
6) Select the vocals and go to Effect>Bass and Treble and insert 4 on treble and press okay. Repeat again.
7) Make sure you have a couple seconds of blank space behind your vocals. Select the vocals and go to Effect>GVerb and set the following:
-Reverb time: 5
-Dry signal level: 0
-Early reflection level: -26
-Tail level: -50
The rest leave default.
8. Congrats you now have a fabulously tuned UTAU! I also use the same thing for my other UTAUs with slight adjustments of course. This is often used with female UTAUs but I don't really use male voicebanks so I'm unsure.