l am ''building'' a tree swing. Is their a safe way to harness myself to the tree in case l lose my footing? Also ratherthan climb the tree to where l need to wrap the rope around a tree limb who has an ingenious way to get the rope around the tree limb without climbing all the way up?

Use a weight tied to a string - throw it over the branch and pull the rope over with the string - do not need to climb at all

Good Luck

As Tahoe said, use a throw-line. Arborists use them all the time to set their climbing lines. Never free climb (climbing without fall protection), & never climb unless u r properly trained. You will only end up damaging the tree or injuring yourself.

After you've got the throw-line over the limb u want it is a simple matter of attaching ur permanent line to the throw-line (a sheet bend works well for this) & towing the line up & over the limb & back down to you. Then, using the running end (the end that was attached to the throw-line) tie a running bowline (do a search for both the sheet bend & running bowline, u will find pictures & instructions on how to tie them) to cinch the line around the limb. Or u can attach both ends to whatever u r using as a seat. Repeat the process for ur second line (if needed) & you're all set.

Beware that environmental conditions (sun, rain, etc..) will soon degrade whatever kind of line u use, so be prepared to replace it on a regular basis.