I have never made an Automator script before today, but I needed something.
If you use DuckDuckGo and don’t want to get too crazy about adding a search option on your contextual menu, you can create this script to add a feature just like the default “Search in Google/Yahoo/Bing”.
Open Automator and choose File > New and choose Service.
Scroll the left pane down to Run Shell Script and drag it over to the right pane.
You should be able to figure out the rest by looking at the example.
Once you save the script, it will appear when you select text and control-click. Depending on how many services are on your machine, it may be under the Services menu.