If you have maelstrom daggers, you can use the following:

HA = Heavy Attack (always on the DW bar)
LA = Light attack (as much as possible)

One of the "classic" rotations is the following:

Bar setup:
DW: Rending Slashes, <flex>, Rapid Strikes, Rearming Trap, Bound Armaments // <ultimate>
Bow: Hurricane, Anti-cavalry caltrops, Endless Hail, Poison Injection // <ultimate>

The flexible slot can be Deadly cloak, Vigor, Dark Deal, Crit Surge... Whatever you feel might be necessary. If you want more abilities, you can still use Overload on your backbar for the utility.

For ultimates, if you use Rend on the front bar, you can use Flawless Dawnbreaker on the backbar. If you use Ballista, you can use Dawnbreaker on the front bar then. Your backbar ultimate is also flexible and might change based on specific bosses (Overload for backyard on Rakkhat, Negate for the Warrior in HM).

The rotation itself:

Rapid strikes > Rending slashes
Rapid strikes > Rearming trap (swap)
Endless Hail > Poison Injection
Hurricane OR Anti-cavalry caltrops (whichever is not up)
[LA > Rapid strikes OR HA > Rapid strikes] (until you have to refresh Rending Slashes)

You have variations where you can add Deadly cloak on the front bar, use Razor caltrops and refresh it every other rotation, have Hurricane on the front bar... etc. Tiny variations, change things around as you see fit.

You have another rotation available with vMA daggers as well, which will require you to have perfect weaving on your backbar (as such, I would not recommend it until much later on):

HA > Rapid strikes > LA > Rearming Trap (swap)
LA > Hail > LA > Poison Injection (swap)
HA > Rapid strikes > LA > Rending Slashes (swap)
Hurricane OR Anti-cavalry caltrops (whichever is not up) (swap)

And repeat. This rotation has the benefit of having a 100% uptime on hawk eye, drastically empowering your Endless Hail and overall damage. IF you have perfect weaving.