I am 55 and used to completely suck with fixed weapons. Now I don't. Here is what I did.
There are two major issues.
1. Range Control
2. Tracking with your eyes.
Range Control
Range Control is a rather large topic and is different based on fa off or fa on usage. Range control is very important because of damage fall off distance. In addition, the most powerful weapons (and fun!) in game are often fixed and short range. The short range blaster rail gun is meta but has a 1 km fall off. Staying within 1km of a high ranked npc Viper 3, is no mean feat.
Tracking
Plasma Accelerators
Multicannons and PAs reticles share the same vector, however the PA reticle is much further out. I use the MC reticle to train my eye to locate the PA reticle. The PA reticle is very deceiving, it takes experience to know if your ship is properly aligned to connect. In general, the closer you are to the target ship, the closer the reticles will be to the target making tracking and successful shots easier. Hence why range control is key.
I used a 4 medium gimballed OC MultiCannon plus one Huge Efficient PA FDL as my " learning to aim PAs" ship. I did hundreds of Czs. I made sure I connected with the huge PA Every. Single. Time. Then, I went to a four PA build with one medium Mc build.
[Edit] Of course one could go immediately mostly PAs and one MC, but the TTK will be much much longer at first. Decreasing frustration in any learning situation is a good thing.
