When hacking with the Hack Tool, it is highly suggested the player do so from cover, or know a covered spot to quickly retreat to. To not do so puts the player in danger from the Security device the player may be hacking (being shot at by a Turret, or detected by a Camera).
When the player encounters a Splicer who has control over a Security Bot, use the Auto-Hack Dart to quickly subvert the enemy's control, and turn the Bot against the Splicer unless you have a Security Command to save Auto-Hack Dart (also, killing the controlling Splicer first disables their Security Bot).
Auto-Hack Darts are most useful for hacking safes, since safes are the most difficult hackable devices. An Auto-Hack Dart is also very helpful for one door lock in Persephone which moves extremely fast. The disadvantage to this tactic is being unable to utilize the blue hack zones during a normal hacking process.
Hack Darts are fairly rare and very expensive, so it's recommended to save them for more pressing occasions. Hacking a stationary Security Camera is usually easy to accomplish manually, while attempting to hack an active Security Bot is a better use for the Hack Tool.
Remember that the Hacking Needle has a limited number of "passes," marked by the number below the screen with the colored zones.
Although it is possible to shoot enemies with the Hack Tool, doing so will deal them no damage, destroy the Hack Dart and alert them to Delta's presence.
The Careful Hacker line of Tonics will slow down the needle's speed during the hacking process, allowing for an easier hack.
EZ-Hack will increase the size of the green and blue zones when hacking a machine.
Hurried Hacker will allow the player to complete a hack instantly after hitting a blue zone. While this can potentially save the player's life if one is attacked during the hack, it'll also limit the number of bonuses one can gain with every hacked machine.
Quik-Hack works in a similar fashion, reducing the number of hacking stages. As with Hurried Hacker, this will speed up the hacking process at the cost of reducing the amount of bonuses one can gain. It is also recommended to avoid equipping Quik-Hack and Hurried Hacker at the same time, as both fulfill the same function.
Security Evasion allows the player to launch a Hack Dart at a security device without being detected.
The Short Circuit line of Tonics will increase the stun time when the targeted device is hit with Electro Bolt. Short Circuit 2 will cause electricity to shut machines down permanently, or until the player hacks it.