With blue sky above (meter the sky - the blue part -), surrounded by nature (meter the nature - the green part, if any -), with near subjects you can rely on the palm of your hand (though you must calibrate/compensate, you hand may vay) with two or three readings. You can also wear (and use as) a gray hat, or a handkechief, or gloves (even black ones) some "coloured" film box could help too! ... Another thing that can help in the very fieldwork to "speed up, is to lower the film speed" (x) stops/steps previously, knowing beforehand that you're going to need "certain (x)" compensation for certain scenes ... And finally, bracket exposures! waste film, that's the way!