I decided a few chapters into a book I'm writing that I dislike present tense, and that I would need to go back and make all instances of present tense past tense to maintain consistency. However, now that I'm going back to change the tense, I'm finding it is a far greater undertaking than I had expected. This is beyond the issue I posted yesterday but likely related to this other on the English SE which is about a specific instance of tackling present perfect during the attempted conversion.
When I search Google for information on my problem, it's all about verb conjugation. I know how to conjugate verbs, but I hope to do more than convey basic information. It's like how you can start every sentence with "noun verb ____" but it sounds terrible.
So I'm asking for tips and hints for converting a present tense narrative to past tense. That or some external guides/aids.
Currently I'm just going through and changing conjugation, and rearranging sentences as I see fit, but it's really painful to read. The prose I've written in past tense tend to look nicer to me than those I've written in present, so I am absolutely adamant about switching to past tense, and I don't want to have some massive tense shift mid-novel. Well, not the middle of the novel, but a fifth of the way in. However at the same time, the present tense narratives I've written don't look bad. I just think they would look better had I written them in past tense initially, but when I convert them in the manner I'm doing now it just looks mangled and ugly.
Post Scriptum (which ended up longer than the initial question):
My reason for initially choosing for certain parts of this book to be written in first person were thematic. I had a reason, but later decided that reason wasn't good enough. However in the process of writing an already bifurcated story became even more so. One side was being written in past tense and developed a cold detachment that suits the characters and setting. The other side, is in present tense and has a fatalism. One MC is a stone wall resisting by force of her iron will, and the other is struggling just to keep from falling to pieces emotionally. As much as I dislike writing in present tense, it lends itself well to this situation, casting a stark contrast on the two sides of the story while emphasizing how each MC fights against fate, and how fate ultimately has the last word. One is slowly losing her humanity, while the other is constantly breaking down, and wishing for oblivion (as I said in another thread, this is a dark tale).
My point is that while everything Baker said is 100% true, as far as I can tell, there may be good reasons to keep the sub-optimal present tense in a story. I just wanted to throw that out there for anyone who might also be in my situation. To be clear though, Baker's answer is still the answer.
Since crying and wishing for a death you can never have wouldn't have the same impact in past tense as it does in present tense, where all the character sees is the immediate and ugly present full of gloom and doom, I'll be rewriting the past tense bit I added out of frustration for the limits imposed by present tense and just learn to work with present tense. It's a challenge and a valuable experience.