The key to a comedy plot is to understand that the term comedy doesn’t imply that the storyline is funny. It can be funny, but my experience of such plots tend to be heart-breaking and painful until the final resolution. Generally speaking comedies are about two people who love each other and are destined to being together being prevented from being together by a series of obstacles that need to be overcome.
My favourite Shakespeare play ‘Much Ado about Nothing’ (where ‘nothing’ refers to gossip and rumours) is an example of such a tale, where Claudio is tricked by malicious gossip into rejecting Hero at the altar in the belief that she has been unfaithful; resulting in her ‘death’. Benedict and Beatrice equally are tricked into confessing love for each other after having been openly antagonistic towards each other.
What the audience knows though that the characters do not is the scheming of the antagonists and other well meaning protagonists working against them. Part of the construction of these types of stories in this format is that the characters need to resolve these obstacles.
‘Much Ado about Nothing’ has two comedic plots. Benedict and Beatrice was easier to resolve by the other protagonists by planting the idea of being admired by the other into their heads, and touching on raw underlying feelings that just needed bringing out into the open. And because they did this, a resolution between Claudio and Hero was able to be achieved and an uncovering of the source of the rumours was able to be openly challenged.
The role of the obstacle in comedy plots can be as diverse as your imagination allows and I use the devices myself in my fantasy writing. In one of my (as of yet unpublished) novels ‘From the Ashes’ part of the plotline involves the two main protagonists being in love with each other but separated by social expectation (as Damen is a low ranked country boy); cultural misunderstandings (on the part of Kara who was raised in a place where love does not exist); and a shared belief that neither of them believed themselves to be worthy of being loved. In addition Kara is persecuted because of her immense magical power, and because of that danger she arranges for Damen to be kept from her to protect him.
As you can see some of the obstacles in comedy plots don’t need to come from forces external to the protagonists; the protagonists themselves can put them in place. For my characters, it is experience of life, confidence and persistence that are needed to help them resolve their problems. It isn’t of course as easily resolved as that when it comes to everyone else accepting them (but that’s for other books) but ‘From the Ashes’ in very much about the two protagonists overcoming the fears they have, before they then can face everyone else.
Another way in which the comedy plotline can be used to great effect is when you have certain character types involved in the love story. One of the greatest examples (in my opinion) is in Frasier, and the long running story between Niles and Daphne. At first the separation is understandable; Niles is married. But Niles whilst a very intelligent and confident character most of the time, when you add Daphne into the mix he becomes bumbling and shy.
If he’d had more confidence in himself and in his feelings being reciprocated they would have ended up together a lot sooner. Then again that wouldn’t have made for the great agony the audience when though waiting for that moment to happen and when it finally did it was so rewarding. Then of course they threw in more obstacles between them, but that’s television for you.
So when it comes to the comedy plotline your imagination is your only limitation. As long as the obstacles are believable and fit with the general atmosphere of your writing then go for it.