Nikon d3000 and d5000?
I know there's a difference between the 2's sensors, but whenever I see all of my friends with the d3000 upload their photos, the tones always appear to look like they are orange-ish and more vibrant.
when it comes to my d5000, the tones are more eh, and not as vibrant. Is this the difference in sensors?
No, more likely in settings.
It all depands on how they put their settings like aperture, iso and shutter speed
but i do think the d5000 is better
You have two choices:
Read your cameras manual and set up your camera to shoot with more vibrant colour or shoot in RAW and use Lightroom to process the image exactly how you want them
The D5000 has a much better sensor, so in theory, it should perform much better than your friends D3000 if you and your friends had similar photographic skills. You may find hanging out with them will enhance your shooting skills
It's the difference in photographers' abilities.