This is an extremely broad question with a lot of complicated answers but your best bet for the average consumer is the that it's the last 2 or 3 numbers that are the most important.

The gtx 760 is not better than the gtx 680 even though the number overall is higher, it's the 80 that matters.

If you compare a Gtx 1080 to a 1070 it's pretty straight forward, the bigger number wins in performance. The first number (or two in this case) are just to mark which generation the cards are from.

That being said a Gtx 760 is much better than a Gtx 480 even though it's an 80 series it's far too old to compete in the modern gaming market.

The same is mostly true for CPU's depending on the series of CPU.

Intel has i3, i5 and i7 (for most consumers) and you'll always know that an i5 4670 isn't as good as an i7 4770. But the i7 3770 also beats the i5 4670 because it's an i7. But an i5 4690K can beat an i7 2600K in some cases (video games that don't leverage multiple cores)

For AMD you basically have Athlon and FX at this point.

FX series the first number is the core count, the second number is the version of that CPU. The 8150 is an early version of the FX series 8 core CPU. The 8350 is a newer version. The 9590 is also 8 cores but an extreme version that nobody should ever buy because it's a waste of money and horrible to manage.

6300 = 6 cores

4300 = 4 cores

Athlon has Athlon x2 and x4. x2 are dual core and x4 are quad core. At that point it follows the same rules as GPU's. The 760K is better than the 850, but not better than the 860K