Having trouble staying alive in Breath of the Wild's Master Mode? Well that's probably because the game is designed where it gets easier the further into the game you get. As such, I've spent a good chunk of my personal time studying and analyzing the best possible tips and strategies that can help you survive the first half of this devastatingly difficult challenge. So let's get started.

1. Stealth is your best friend. The enemies you face may be powerful, but they're dumber than a sack of hammers and are as attentive as deer in the headlights. Be as quiet as possible when approaching from behind and you might be lucky enough to deal a critical strike on them or even steal one of their weapons before they realize you're there, but if you accidentally alert a hoard of them just run away and hide; they'll eventually lose interest.
2. Stalfos are extremely frail. Despite their intimidating nature and powerful weaponry, stalfos of all kinds can be easily dispatched with a headshot from your bow. Be true with your aim and they'll topple like a house of cards.
   
3. Fight smart, not hard. In many cases it much easier to have the environment do your fighting for you. Keep a look out for boulders to push off a cliff into a small gathering of enemies below or something hanging near campsites that will cause some chaos if it is severed from its tether.
   
4. Find the DLC Equipment. The Phantom Armor and Majora's Mask are invaluable very early in your adventure as the Phantom Armor has a combined defense of 24 and each piece in the set raises your attack power by one level, and Majora's Mask makes most monster types ignore you unless they are threatened. Be extremely careful when procuring these pieces of equipment though as they are all found in enemy territory.
   
5. Be confident in your abilities. Unless you are absolutely certain in your skill level and equipment, DO NOT engage a lynel. Early in the game these monsters are death incarnate and many will be equipped with bomb arrows.
   
6. If you own amiibo, use them. No matter what the amiibo is, scanning one will give you a small handful of food or materials that will definitely help later. Even better, if one of the amiibo that you own is Wolf Link, then you have a partner that will help you fight the many beasts that stand between you and your ultimate goal.
   
7. Study your cookbook. Remember when cooking meals or mixing potions that the right ingredients can make all the difference. Combining ingredients with different attributes will cancel them out so be sure to use like-named foodstuffs like "mighty" or "armored." Also, dragon parts are not classified as alchemy ingredients; they're considered seasoning, so be sure to use them in food instead of potions with their horns having the best effect.
   
8. Ancient arrows = death from above. If you happen to find a few ancient arrows on your quest, save them for when you are REALLY in a pinch. With perfect aim and the right bow equipped, these arrows are strong enough to one-shot a silver lynel. However, enemies are instantly vaporized when shot with these arrows so you won't be getting any spoils from them. Plus getting this ammo replaced is a rather expensive endeavor so only use them if you have no other choice.
   
9. Be a shutterbug. After you get the camera rune, take pictures of everything the next time you come across it. If you are having trouble finding ingredients and materials for armor or stealth potions, you can set them to the sheikah slate's sensor so it will ping when you get close.
   
10. The best offense is a good defense. Good shields are a commodity early in the game so mastering the perfect guard is a must. Even a pot lid won't lose any durability if you manage to successfully parry a guardian's energy beam. Also, shield surfing will wear your shield down faster than any form of combat; avoid being Legolas until you can easily get more shields. If you're brave enough, a good strategy would be to sneak into Hyrule Castle while wearing Majora's Mask so you can more easily obtain the Hylian Shield from the Stalnox in the castle's dungeon keep. That shield can last for an absurdly long time, but once it breaks you won't be able to replace it until the Tarrey Town side quest is finished.
    
11. Elemental weapons: Your own personal climate controller. Flame and frost weaponry are not just effective in combat, but when sheathed on your back they can keep you warm in cold climates and cool in hot ones. This is important to know if you run out of meals and potions that give you those benefits.
    
12. Take advantage of weather conditions. While it may be dangerous to travel out into a thunderstorm with a bunch of metal equipment, it may be a good idea to take at least one rusty weapon with you. Since the lightning will be attracted to the metal, you can use this to your benefit by throwing the blade at your victim's feet at the last second and have the gods smite your foes for you. Just be sure you don't get electrocuted in the process.
    
13. Gotta go fast. Even if you aren't going to do the trial the moment you arrive there, activate the shrine anyway. The more fast travel points you have, the better.
14. Ration your weaponry. Never, EVER, throw a weapon at an enemy unless it is a boomerang or it is already getting ready to break. Once a weapon is thrown at your foe, it instantly shatters meaning you now have one less pointy stick to defend yourself with. Also, some enemies like ice wizzrobes and fire lizalfos have elemental weaknesses, so you can prevent a lot of unnecessary weapon damage if you slay these fiends with the blade or arrow that has the element containing the polar opposite of the monster's name.
    
15. Full body baptism. With the exception of lizalfos and octoroks, most enemies cannot swim. If you can somehow lure them to deep water and knock them in, they will drown and die instantly. This feat can be achieved much more easily if you have Kilton's spring hammer.
16. A link to the past. And last but not least, if you've already played through the game on the normal difficulty setting, great! Use your memories of your previous playthrough to breeze though the side quests with ease.

Well that's all the info I can summon from my research so I certainly hope it helps. If you're still having trouble, then I have no idea what else you can do but to start farming for fairies; they might be able to keep you alive for a little while longer. But until then, I'll be seeing you.