Sex and nudity. Airgh. These are two things that I'm really getting tired of seeing over-used. I get that they are part of a natural relationship, and I'm not trying to prudish here. I just think that there can be too much. The problem is that they are used primarily to shock people. After the twenty-seventh orgy, what will shock me is a couple kissing. So let's see if we can set some ground rules for better use.
[Note for morons: These rules do not apply to erotic comics, or comics where the idea is to have fun with sex and nudity.]
Nudity is best used symbolically. There needs to be a reason for the nudity that works best for the story. If you need to show characters at their most vulnerable, when they are in an area where they do not need to pretend, such as among friends or in an intimate moment, nudity works. But it also works for showing the wounds of someone who has been attacked. If someone needs to wash herself of some sort of spiritual crud or to clean herself, then have her go swimming or take a shower. The same applies to ironic situations; putting a gay boy in a shower with straight males where he simultaneously enjoys the view but is afraid of getting an erection is stereotypical for a reason. It can be used rather well to show someone who has no fear; nothing says "I am not scared of you" as walking past them naked.
Don't use nudity just for titillation. Yeah, I get that forcing someone to be naked in public can be a show of power. You can also use nudity for humor, as long as you understand why someone would want to hide their secrets. A woman flashing her breasts is also great for comedy, especially if it's directed towards authority or a virgin. And we won't talk about the mercenary who decided to streak as a way of diverting everyone's attention away his escaping friends. But...having a character walking around naked just to have the character be naked is a waste of time. Make sure that there is a reason for the nudity; just like any other costuming choice, make sure that there is an actual reason for it.
The same applies to sex. Sex is based used for intimate moments, and expressing moments when you want two or more characters to demonstrate an intense attraction to each other. From a writer's perspective, sex needs to be treated as more than just a natural function; it needs to be treated just like everything else, and to have a reason for its use. Again, not trying to be a prude; you'll note that not everyone feels comfortable going to the bathroom in front of others, but there is no better way to show that the person simply doesn't care about what others think or is willing to break conventions than by defecating in front of others. Sex shows that the person is willing to do whatever they want, and they only care about the pleasure or the politics and they don't care what others feel about their doing so.
Don't use them just to shock the audience. In all honesty, if the only reason that you are including nudity is to shock someone, it probably won't shock anyone. Sure, your artist friends will say it's shocking, but odds are they are either bored by nudity or just want to see boobs. It's unlikely that prudes that will even see the sex or nudity. So if the only reason you are including sex or nudty is to shock someone, don't. It's not as artsy as you think it is, and only beginning critics, the ones you should be ignoring, think it is.
If the only way you can make what you are doing fun for you is to add sex or nudity, do an erotic comic instead. I am so tired of seeing something that is pretty much drek if you take out the sex or nudity get critical acclaim and popularity. I love training scenes; they show what the character goes through in order to do what they do. But if the sole reason you are including a training scene is so that you can have the character shirtless, then find another way. I'm all for pin-ups, but putting a pin-up as part of your story is just a waste of time, and it breaks up the story in a bad way; you should never do anything to take a person out of the story, and nothing better than having something that is nothing more than eye-candy. Do pin-ups, just not as part of the main comic. Use it for voting rewards or something that donors get, but do not use it in the comic itself.
I'm obviously not saying don't do it. But, like everything else in your comic, have a good reason for doing it.