edit - Wow, i went from low tier 2 to low tier 3 CA in a day....lol.
Mistake, sorry but I am still not Tier 1-2 in FFA or CTF.
Accuracy is up to 27 percent now.
Before you can rail good you need to find a comfortable sensitivity , try to get a sensitivity that you can do a easy 180 or 360 depending on your play style and mouse speeds. You want to be able to track the enemy as you move so if you have trouble tracking play with your sensitivity settings, usually I only move up in .15 increments till i feel comfortable and I can track the enemy well. You can try to mess with M_pitch settings try 0.013 makes your mouse a lot smoother but slower when aiming up or down and should help a lot in over shooting/over aiming situations. This is just preference however as each Computer, Mice, operating systems, mouse rate software, removing windows accel with a registry file, etc the sensitivities vary, 5 for me may feel like 3 or 10 for you...
Something I used to do (18 years ago) was turn on impact marks so you go to a empty server or practice mode and aim for a spot and hit it then try a flick rail to try and hit that same spot, move around see if you can still hit it, try 360 rails or something to learn your sensitivity and control. Toss a Xaero bot on there or Klesk in Nightmare they dont miss much but its good practice for learning your sens.
Rail is muscle memory coordination just like a lot of the weapons in quake. Flick rails are ok in certain situations try messing with cl_mouseaccel if you have trouble with flick rails and tracking just use .01 to start and .02 etc etc i use .015 just play around with it to find something your comfortable with. You may not even like accel but it does make tracking like butter if you find that sweet spot.
Alot of it is movement and predicting enemy location after the first rail shot (where he will strafe/move to once he gets hit) , also depends on the player some players move better and can dodge rail pretty well after getting shot once, watch for jumpers there easy to rail, people that follow a pattern.
You can mess with the cg_railtrailtime to help as well, makes the beam last a little longer before it dissipates to know when to fire your next shot you can use it to line up shots and get shots in better positioning on the map, then set it back to default when you get comfortable.
Get comfortable with a cross hair, I recommend the open cross which is cross hair 2 cg_crosshairsize 23 or 24 (like old q3/q2 defaults) and force enemy model with Keel/BRIGHT , TankJR is bigger then the HITBOX/HITSPHERE so tho he can be railed most of the time your rail goes through him. Once again this is user preference depending on your settings...
Enemy color is all user preference you can go BRIGHT GREEN, the easier it is to see the models easier it is to rail them. I like the Bright green Torso and Bright CYAN blue legs you can see it all day, but everyone has there own colors they like its on you.
now cg_FOV depends on you, 90 default is close makes bigger targets but everything feels slow , 100-110 things move back a bit farther its easier to see around corners and it improves your rail (for some it dont just depends on the player) but it also makes it seem like you move faster.
most important once you feel comfortable with your settings DON'T CHANGE THEM unless its necessary, Quake is all muscle memory coordination the more you change it the more you gotta re-learn the muscle memory and you will never get better just STICK WITH IT and make slight changes if needed... Happy Fragging...
sc(+)pe* (quake live please add symbols so i can be me again)