So my guitar lately hasn't been holding it's tuning as well as it should, especially when I'm playing in Drop D tuning. The tuners I'm using now are just Peavey Stock tuners that came with the guitar. I play a Peavey JF-1 EXP Semi-Hollowbody.
I understand that the problem may very well be the tuners themselves, however at the moment I don't have the money to buy new ones.
If it's the way I'm stringing the guitar - though I'm positive it's correct - I'm including the video I watched ages ago that showed me the 'proper' way to string it.

If anyone can provide some solutions for me, that'd be much appreciated.

Cheers guys!
it could be with the nut, rub some chapstick under and on top of the strings and see if that helps any.

Ibanez RG7621
Ibanez RG121
Stringing shouldnt really take a big effect your tuners. The fact that they dont stay in tune very well is probably because your tuners arent very good. So change them.

I know you said you dont have the money right now, but maybe an alternative would be use less thick string guages. Depending on if you use heavy guages or not.
Are all the strings going out of tune? If it's just the D then maybe the string has to adjust to the tension
Okay well here's the thing, is that the nut happened to chip at some point around the low E only. The tech guy I deal with built it back up with ceramic foam and it was holding the tuning fine before. That was about almost a month and a half ago. As of recently it's been going out of tune. It's a little bit on each string, but mostly on the low E when its tuned to D.
Hope that helps the situation a bit