Most tackle stores are happy to spool up your reel, particularly those who have a line winding machine. If you have the time, and they have the quality line you want, let them do it.
When you’re spooling up a bait casting reel, or any conventional reel, put a rod, or even a pencil, through the center of the line spool. Tie the line to the reel with a (Uni-knot or Arbor knot) clipping off the tag end. Snug the knot to the reel spool. One person should reel while another holds both ends of the rod, applying pressure as the line is reeled onto the spool. Fill to about an 1/8 inch from the spool’s outer rim. Keep the line away from anything that could cause abrasion.
Use the same procedure with a spinning reel, but reel line so that it comes off the end of the spool. After 15 or 20 turns, if a twist occurs, turn the spool over and continue to fill the reel.
Monofilament will twist. If it happens while fishing from a boat, play the line out with nothing on the end, trolling behind the boat for about five minutes. It is also important to always use a ball-bearing swivel, which will reduce or eliminate line twist. Certain lures or bait tied directly to the line will invite twist. To compensate for this, try lighter line. Just for your own education and enjoyment, go down in line test. You will be surprised that you can catch big fish on line much lighter than you are presently using. It may take more patience and even a little more skill, but you will enjoy it. If fish stop biting, go to a lighter test. The thinner line may get them eating again. The thinner the line, the less likely a fish sees it.