Rate Control Methods
There are various rate control methods available in q264, and a full description is out of scope here, see the q264 documentation. However, it's interesting to see the per-frame PSNR of the various rate control methods.
This chart shows the VBR, AVBR, and CQP rate control methods on runs with approximately the same resultant bitrate. The Constant Quantization Parameter (CQP) rate control method has nice uniformity across the scenes. Even though its overall mean PSNR is lower it is probably a good first choice for rate control methods. Unfortunately CQP is a coarse integer control; the bitrate changes significantly from one setting to the next.