Simple:
* The snow began to accumulate on the roof.
* He accumulated a large collection of stamps.
* Over time, dust accumulates on neglected surfaces.
More complex:
* The company accumulated a huge debt over the years.
* She accumulated a vast amount of knowledge through her travels.
* He was able to accumulate wealth through his investments.
Figurative:
* The tension in the room began to accumulate as the deadline approached.
* He accumulated a lifetime of regrets.
In a specific context:
* "The leaves accumulate on the forest floor, providing nutrients for the soil."
* "She accumulates knowledge like a sponge, absorbing information quickly."
Remember, the best way to use "accumulate" depends on the context of your sentence and what you want to convey.