If you're at a high enough altitude begin your slow descent to your landing spot but keep moving! A 12-13 mph airspeed, not groundspeed, should give you the most efficient flight home and if you're descending all the way, that helps, too. If you are fighting a wind home, well that was poor flight planning, so always have a plan B you can go to and constantly evaluate your options as you vector home. Those that Scuba dive may be familiar with the rule of thirds, also applies here. I try to plan my flights as if I were over water and landing anywhere but home is not an option, so I plan them so I consume about 30-40% battery to reach my objective, leaving 60-70% to get home in case there's a problem along the way. After repeating the same course several times, then I gain a little confidence to push it a little more.
As long as you're moving, it shouldn't matter if you're in ATTI or GPS mode, but if you're hovering in a strong wind, then yes, GPS mode will consume more power as it fights to hold position in space. If you're on flat ground then get low where the surface winds are usually less than say, 100+ feet up.