Verbs:
* Go: Go walk
* Take: Take a walk
* Start: Start walking
* Finish: Finish walking
* Continue: Continue walking
* Stop: Stop walking
* Begin: Begin walking
Adjectives:
* Short: Short walk
* Long: Long walk
* Quick: Quick walk
* Slow: Slow walk
* Easy: Easy walk
* Difficult: Difficult walk
* Pleasant: Pleasant walk
* Daily: Daily walk
* Morning: Morning walk
* Evening: Evening walk
* Lonely: Lonely walk
* Peaceful: Peaceful walk
Adverbs:
* Quickly: Quickly walk
* Slowly: Slowly walk
* Carefully: Carefully walk
* Confidently: Confidently walk
* Happily: Happily walk
* Sadly: Sadly walk
Prepositions:
* On: Walk on the beach
* In: Walk in the park
* Around: Walk around the block
* Through: Walk through the forest
Nouns:
* Dog: Dog walk
* Baby: Baby walk
* Group: Group walk
Other:
* Just: Just walk
* Let's: Let's walk
* Would you like to: Would you like to walk?
This list isn't exhaustive, but it should give you a good starting point for words that can go before "walk." The best choice will depend on the specific context.