Right now I have a ViewPager with two different Fragments, and I currently indicate to swipe left and right with two chevrons. However, someone might mistake those icons for buttons, and I would like something that indicates a swipe in an intuitive way that doesn't look like a button that they can click on.
I've encountered a similar problem and solved it by simply adding animation to reveal the "hidden" bits.
If the user taps somewhere on the element, you can add a bounce effect which momentarily reveals the next/previous pages. From my own user testing this is a very intuitive way to show the users they can swipe.
Example: GIF of demo.
A few options come to mind:
Adding a page indicator: a row of dots/bullets/circles with the active one different from the rest. This should alert the user to the existence of other pages than can be reached by swiping.
“Shaking” the page a bit when it first appears, showing part of the other pages.
Add an overlay with explicative text and/or graphic, probably only the first time.
A combination of the above.