How to deal with a lot (250+) of settings?

I'm currently working on an Android application that has a lot of (over 250) individual settings. During most of the app's existence there was no designer working on it, so the settings UI is mostly (categorized) lists and dialogs.

It is an email client, so some of the options are server-related, but most are about customizing the app. Some setting affect others in different ways.

A lot of our users have spent time customizing the app and they seem to love all the customization abilities. However I'm worried that new(-er) users may feel intimidated, get lost, have difficulty finding what they need, and so on, therefore abandon the application.

We have a search function in the Settings screen, but what else can I do? Are there any best practices for cases like this?

Thanks a lot!