How can I improve the quality of my emulations?

So I just downloaded a PS1 and PS2 emulator on my laptop. My laptop isn't great, but I am building a relatively strong gaming pc within the next few weeks and would really like to know how I can get the best resolution out of older games. I'm pretty new to emulation, and although ive figured a lot out, anytime I make changes to the configurations on the emulators the games tend to crash upon opening.

So basically Im using epsxe190 and PCSX2 1.2.1. I've been emulating final fantasy 9 and final fantasy 10 so far, but the graphics could definitely do with some improvements. What are some good pixel shaders that can do this and how can I make them work with the emulators that I am using?

Also, for the likes of ff9 the sound tears in the open world, or during fights when spell effects need rendering (I imagine this has to do with my laptop, as its just an average system but would think it could handle a 16 year old game). Is this something that happens just because it isn't reading info off the discs? Is there a possible way to prevent it if it's not due to my PC?

i can't decipher if your using ISO's or the actual CD and the CDrom drive from your post.
i never played anything above ff7, so dunno if ff9 is ps1 or 2.

but ill mention, I've heard some people have issues with certain ps1 game audio, If the Image isn't ripped to .bin/.cue, and maybe needs to be mounted on a virtual drive such as DaemonTools first. I don't have the specifics, I have limited experience with PS emus and never experienced those issues myself. back in the day I always ripped them myself to bin/cue anyway with Clonyxxl and CloneCD. keep in mind this also may have been around epsxe v1.6 or older, which might of only used DX7

but if your not using any CD image in the first place, and just running it from CDRom, that maybe the only issue. Its usually faster and more bug free running it from an image on your HDD.

I don't know about ps2 emu's at all, but ps1 can really run on a garbage pc and be Ok.. unless maybe if its a low AMD cpu. I don't mention GPU... i forget the acronym, but all modern CPUs i believe have build in IGPs on the CPU die, and there all more powerful now than the old low power GPUs which were good enough for ps1.

Im guessing theres tones of shader packs out there, the only one i think i had tho was named somethign like.. Petes OGL shader pack for epsxe. if u have a old CRT around tho, to emulate the old games on, that comes much closer to the original look, unless thats not what your going for.

concerning epsxe, changing certain config options without deleting the old settings file or registry entry it saved may cause the crash as u described, or so Iv heard. I would also imagine unintended behavior maybe caused by running emu's on OS's they weren't designed for, example I heard win8 and 10 arn't friendly towards emu's.