An important tool of the trade of more or less every pirate - just as important as the ship itself, some guns and a jolly roger - is the directional scanner. It is the hunter's track hound, health insurance and lifeguard.
Using the directional scanner effectively requires quite a bit of practice and expertise. When scouting out a system or narrowing down a promising hit, it can be a real hassle to fiddle with direction, range and angles, all the while trying to stay in "rhythm" with that nuisance known as "recalibration".
Everyone can scan with the range and angle cranked up, easily checking their surroundings for certain malefactors. Luckily for said malefactors, lots of people lack a bit of consistency in that regard. And if they also didn't bother to change their ships' name - revealing their identity and how harmless they indeed are - they can expect to be devoured by those malefactors very soon. Which they don't; otherwise they wouldn't have made themselves comfortable in shark waters in the first place.
If there is a pattern in a target's movement, it will be identified and exploited with the help of the scanner. Sometimes it might be more fruitful to first observe a target and how it moves between the belts instead of jumping straight into the belt, possibly landing far off the target. Maybe trail it a bit longer and check at which distance the pilot warps into the belts. There have been kills I just had to wait for in a certain celestial and at a certain range.
I remember one pilot who managed to evade my efforts two times, because my anticipation was faulty at first. But each time he followed the same path: I land, he warps to a station and docks up. After a while he reappears and heads to a cluster out of scanner range. Then he comes back to the belt where I made him leave some unlooted wrecks. So the third time he docks up, I just stay right where I am. He undocks, disappears on scan shortly after, only to head straight for the wrecks. Lock, point, nom.
Of course situations like these only occur with pilots who don't use the scanner and are apparently unaware of the information local coms provide. If however a pilot does use scanner and local coms, being actually somewhat prepared (gasp!) for a little trip into lowsec, it can get rather tricky. You may have to utilize the scanner to its full potential to finally catch those targets. Other factors naturally are instincts, experience, mindgames and a tad bit of luck. Though you won't get to worry about those if your scanning cannot keep up.
When confronted with seasoned pirates, there is very little hope of ever catching them if they don't want to fight you. There are possibilities besides probes and traps, however, portrayed nicely in this little anecdote:
Lisbaetanne is a system frequented by the HellFleet, who established themselves as neighbours of The Tuskers again after a span of absence from Essence. HellFleet's second in command Eviwyn also happens to regularly make kind of a mess in there. Previous engagements between us didn't go so well from her point of view, which is why she's usually a bit reluctant to fight me.
I therefore had to take a different approach in order to have a shot at her Jaguar for once. I knew of one of her safespots that was rather close to a belt, but still way off for the overview to pick up on her. A bit of scanning at different ranges soon revealed that she was about 378,200km away from the belt's center. Subsequently narrowing down the angle to 5° determined her whereabouts to be between the belt I was in and another one.
So I roughly knew where I'd have to land to have a slight chance at getting a hold of Eviwyn's ship. I guess you can tell by this whole endeavour that I was extremely bored, but covering 378,200km at sub warp speed would have been a rather excruciating experience. Instead I buzzed around between the belt and the other cluster's planet while dropping a load of bookmarks.
Eventually I had a bookmark at almost the perfect distance from the belt and I could freely chose within 100km where to land from it. Only one problem remained - Eviwyn's ship appeared to be moving, ready to instantly cheese it should I actually manage to get close enough. My only hope was to catch her napping.
Again with help of the scanner's range adjustment I monitored her position, waiting for the appropriate moment to enter warp. 378,180km away (hm, did I do the math right by the way?) ... 378,170km (eh, probably not, whatever) ... 378,160km; there, warp to bookmark at 50km!
To my actual surprise, a red flashy Jaguar did indeed appear on my overview. My calculations weren't quite perfect however, as I landed 20km off. But in the end it didn't matter, as Eviwyn naturally was on her toes and warped off before I was able to lock her.
Even without the fight this incidence is a prime example of what the scanner is capable of. Not only in terms of me tracking down a ship in open space, but also in terms of the target knowing of hostile presence and being prepared for any turn of events.
To sum it up, there is no excuse not to use at least the basic functions of the directional scanner. As far as pinpointing evasive ships goes, there is no way around constant practice. The occassional customer actually asks me how I was able to keep track of them the whole time - yes, some people don't even know the scanner exists. Blessed art they.