The best way to ensure no interference is with separation (and good grounding). Short of good separation, make sure the cables don't run parallel to each other throughout the run. That is, twist the two cables over each other, over and over again, all along the way. In effect, you braid the cables together like braiding hair or rope - only with two cables. This crossing over of the cables will prevent/cancel out any "eddy" currents from being "induced" into adjacent cables.
If you look at common CAT-5e Ethernet cable, you will note it is "UTP" - unshielded twisted pair. Within the Ethernet cable, there are 8 wires in 4 pairs. Each pair is twisted together all through the cable, and all 4 pairs are twisted around each other all through the cable. The angles of these twists are actually at a predetermined angle based on the frequency of the signal running through the cable, to maximize the attenuation/cancellation of any energy robbing interference. By twisting the wires in this way, they don't have to use shielding around each wire, and around each pair of wires in the cable. This greatly reduces the cost of CAT-5e cable, allows for much greater flexibility, and smaller size too.
I hope it illustrates what you should do here.
One more word of caution. Do
NOT tape them "tightly". The thickness of the insulation around each wire is not arbitrary. It allows for proper separation. If you smash the insulation, you reduce the distance between wires and that may cause interference issues. In cables that carry higher voltages, it can results in shorts. So you only want to tape them to hold them together "loosely".
That said, I recommend
cable ties instead of tape. Tape turns ugly over time, comes loose, attracts dust bunnies, and leaves a sticky mess when removed.
