TextExpander and OmniFocus are two of the first tools I install on any new device, so it's no surprise that the two work well together. You may expect some kind of Applescripting or shell magic, but I keep this extremely simple and only use true text expansion with OmniFocus. I run the scripts manually or behind the scenes with Hazel.
xwait = "Waiting for "
This is easily the most commonly used snippet I have for OmniFocus. Any time I need to create a new Waiting For task, I always type xwait and keep going. It's not a huge savings in one instance but multiply this by the average 20 uses a day and it really adds up.
xresp = "Waiting for response from "
Similar to the first, I use this one a lot. I receive and send a ton of email. Any time I send one that warrants a response, a new task is created and this is where the naming starts.
xplan = "Plan project for "
Most of the time when I decide to take on a new project, I don't have time right then to plan it out. So I use this to create a task for the planning process.
xpfm = "Plan for meeting re: "
I don't use this as much as I used to, but this helps me create a new task as a reminder to review meeting materials and get resources together for a call.
xlook = "Look into "
I do a ton of research to help me get better at a project or learn how a new process works. I always start these tasks with "Look into" as an indicator to Google, read, or learn about the item.
xdwc = " (Delete when complete)"
I stole this one from Kourosh. I sometimes have repeating tasks that are creative in some form or don't have a clear definition of "completed." I augment the end of the task title with "(Delete when complete)" so I know to delete the task instead of check it off when I'm done with it. That will keep it from repeating when it's done and allow the project to move on.
x5tom = "5am tomorrow"
Occasionally, I need to push a task off until tomorrow. When I do, I use this in the Defer Date field to push it out one day. I could hit the "+1 day" button but this is habit.
Overall, this is extremely basic compared to what is possible. But this does all I need, there's no point overcomplicating it.