Use it for stationary mid-long range targets (or easy to track targets), the bullet travel time and the gun's slow fire rate makes it hard to use on moving targets and for some reason it misses extremely close targets.
When using multishot mods you can decrease the spread of the extra shot(s) by zooming in, or fire from the hip to increase the chance of headshots (as the multiple shots will spread out slightly)
The Seer has reasonably strong recoil when zoomed in. Consider using Steady Hands to make it more controllable; when maxed out, the Seer's recoil should be almost completely unnoticeable.
The Seer is one of three unique weapons that have a critical chance of 0%, making it incapable of dealing critical damage. As such, critical chance (ex. Point Strike) and critical damage (ex. Vital Sense) mods have no effect on this weapon. The other such weapons with a 0% critical chance are the Miter and Panthera.
Though the shot explodes on impact, the effect is purely graphical. This weapon has no blast radius/area of effect.
Multishot can be observed with long range shots, but is not noticeable short-to-medium range.