One of the major features in Drafts 2.5 is the ability to create custom Dropbox actions. The most common use case that I've seen for such actions is to prepend or append a log file in a Dropbox folder.
I will show you one use case that I've been using personally to log every time I fill the gas on my car. In this example, I will use a text file named L1187CS.md, which indicates the car's plate number. Feel free to change the file name according to your preferences. Using this approach, you can have a separate file for each car that you have.
The idea is to prepend the following information in the text file:
[[time_short]] $[[title]] at $[[body]]/gallon
Each line indicates one gas fill up event. By inserting the new event at the beginning of the file, I can have access to the most recent event first. For each event, I want to log the exact date and time, the amount of money I paid, and the price per gallon. With this approach, I'm using the first line of the [[draft]] as the total amount of money I paid, and the second line as the price per gallon. Obviously you can replace the above format with another format that suits your needs.
Requires: Drafts 2.5, Launch Center Pro 1.1, Dropbox
You can create the Dropbox action by entering the information as indicated in the above screenshot. Feel free to change the folder location, file name, and text template as you see fit. Alternatively, you can open this link on your iOS device to directly import it in Drafts, and then edit it to suit your needs.
The problem I used to have when filling the information at a gas station was I need to do it as quickly as possible. With a Drafts action, I still need to switch the keyboard to a numeric pad, and scroll the actions to find the correct one. To save time, I decided to create a Launch Center Pro action that would prompt me with the correct keypad in the correct order, and have it invoke the appropriate Drafts action automatically. This chain of actions has allowed me to log the info in a few seconds with minimal hassle. As of now, I'm returning the action back to Launch Center Pro, but you can modify this action to have it invoke other apps/actions.
Here's a snippet that you need to copy and paste into the Action Composer in Launch Center Pro:
The only thing I wish Launch Center Pro or Drafts has is a feature to get the current location data. With location data available for scripting, logging actions can become even more informative.