There's ALOT you could do. My best suggestion is to flip through the picture threads and see what others have done to get an idea on what you'd like to do. There's many cheap mods and improvements that you could do. I always suggest looking into replacing your headlights and corner lamps to something better.... like these that you can purchase off eBay...
http://www.ebay.com/itm/98-00-FORD-RANGER-CLEAR-HEADLIGHTS-AMBER-CORNER-LIGHT-4PCS-SET-/121041516504
Also, please create a signature telling us what you've got...ie: year, trim level, engine, 4x4 or 2wd, mods, etc...
As for the blinker mod, it's a pretty simple modifcation. Pull out your signal/corner lamp, snip the ground wire for the corner lamp, crimp or solder on an extension and splice it into the turn signal hot of the turn signal. Gives a really cool look. With the running lamps off, the corner lamp will blink with the signals. With the running lamps on, the corner lamp will alternate with the signals.
Here's a video I did when I was doing the mod for a friend of mine (and installing my retired mirrors)
[ame]http://www.youtube.com/watch?v=U3T-X5623qo[/ame]
And also a better video showing all it's modes but on my Gen5 '01+...
[ame]http://www.youtube.com/watch?v=dNi0nURasXU[/ame]
Welcome to the site and the world of Rangers! Please don't hesitate to ask questions and post up your mod progress!! But don't forget the search feature. You should post pics to this thread!!! It'll give us a good idea on giving you ideas and where to go with the truck.