A perch or tactical is a bookmark located at least 150km away from a fixed object, typically a stargate or station. You should make perches in systems you frequent. Warping to a perch puts you on grid with your target so you can observe the target at a reasonably safe distance that also allows direct warping.

• Be careful with inline and straight up (or down) perches. Being more common, these are less safe. But you can use them to warp in on enemies.
• 150km is minimum warpable distance
• Perches farther than 150km are safer, and it's good to have variety
• Several perches (at least 150km apart) can help you avoid enemies trying to burn towards you.