Does more wraps always mean more resistance?

Yes, for the same wire and inner diameter, adding wraps increases resistance because you're adding more wire length. But if you change wire material or gauge, the relationship shifts. A thicker wire (lower gauge) has less resistance per inch, so you might need more wraps to hit the same ohms.

How do I know what resistance to build for my vape?

Check your device's wattage range and the recommended resistance printed on the tank or mod. A regulated mod can handle a range, but staying within the recommended range gives the best flavor and coil life. For a quick check, use the Coil Resistance Calculator to see what your build will land at.