Your ships sensors have five main stats:

• Targeting Range
• Sensor Strength
• Scan Resolution
• Signature Radius
• Maximum Locked Targets

Targeting range and max locked targets should be pretty self explanatory, they are the maximum range you can target out to and the maximum number of targets you can have locked at any time. Sensor strength is doesn't directly effect your locking at all, but instead determines how well your ship resists ECM, a high sensor strength means lower chance for ECM to land. Scan resolution is what determines how quickly you lock onto a target, a higher scan res means faster locks.

Signature Radius is how EVE measures the 'size' of your ship.

This wouldn't be Eve if we couldn't change all the stats of our ship and our opponent's, and we have quite a few options

• Increasing the Long Range Targetting skill will give you a 5% bonus to range per level.
• Fitting sensor boosters or signal amplifiers, or being the target of remote sensor boosters, which is improved if you load a targeting range script into the sebo or remote sebo(at the cost of the sebo's other effects)
• Being the target of a sensor dampener (and it's made even worse if they also load a targeting range script, though it loses other effects)
• Fitting warp core stabilizers massively reduces your lock range

Bear in mind your max targets is capped by both skills and your ship. So if your skills allow for five targets but the ship only allows you to have three locks, then you can only have three locks at a time. Similarly if you only have skills for five locks but your ship allows seven you are stuck at five target locks. There are very few ways to adjust your max targets

• Training target management skills ups your max targets
• Fitting an automated targeting system gives you +2 max target locks, even when it isn't running. (When it is running you it automatically locks onto shit, which may not be what you want)

Most of the modules that effect targeting range also effect scan resolution.

• Fitting sensor boosters or signal amplifiers, or being the target of remote sensor boosters, which is improved if you load a sensor resolution script into the sebo or remote sebo(at the cost of the SeBo's other effects)
• Training the Signature Analysis skill
• Zainou 'Gypsy' Signature Analysis implants
• Someone in a fleet command role has leadership you get a nice little bonus
• Being the target of a Sensor Dampener (and it's made even worse if they also load a scan res script, though it loses other effects)
• Fitting warp core stabilizers massively reduces your lock speed

Electronic Warfare is weird, just go read the actual page about it.