A bad pull can nick insulation, get stuck, and cost you hours. Fish tape: the standard tool for short to medium runs. Greenlee makes the best fiberglass fish tapes - they flex without kinking and are non-conductive. Steel fish tape is stronger for long runs but conducts electricity and kinks more easily. For runs with multiple bends, a fish tape can bind at every bend.
Blowing wire: for long conduit runs (100’+), a wire/cable blower with foam piston and mule tape is the professional solution. Blow the foam piston through with compressed air, then the mule tape gets pulled through the conduit. Attach your conductors to the mule tape and pull. For very long runs, a power puller or tugger does the pulling.
Wire lubricant: use it. Always. Ideal Yellow 77 or Greenlee Wire Pulling Lubricant. Don’t use WD-40, petroleum jelly, or cooking spray - they can degrade wire insulation. Apply lubricant to the wire as it feeds into the conduit, and apply generously at every conduit fitting.