As the branches of this tree are densely packed, the best way to trim it is by trimming the branches in sections, starting from the top and working your way down. You can use a saw or pruners to cut the branches, making sure to make clean cuts and avoid damaging the trunk or the surrounding branches. Make sure to trim the branches that are blocking the lights or ornaments, and also trim any branches that are drooping too much. Make sure to trim the branches in a balanced manner, so that the tree looks evenly trimmed and symmetrical.