Oh, and here I am with baby 300 hours.
>Gear Progression
In LR and HR, focus on Attack Boost and Health Boost gear. Progress your weapons as normal.
Defender armor and weapons are meant to speed you straight to Iceborne if you just want to rush it. If you own Iceborne, the game will automatically give you the armor set. The Defender weapons have literally a single item upgrade requirement, which will always be a monster's common drop. Moreover, their damage always puts them ahead of the gear you'd be getting at that rank.
When you get to MR, the three first required quests are all done in expeditions for a reason, they you have unlimited faints since you'll be going into those instances with with HR or Defender gear, and that won't be enough to to save you getting 2 or 3 shot from Beotodus, Banbaro, or Viper Kadachi. Those expedition instances are special in that the targets never leave the area like monsters can do in regular expeditions, so take advantage of it. Seriously, take advantage of it, I made the mistake of taking Viper as a regular quest after sighting him, and I almost dropped the game for it.
MR Jagras is easy. Farm him up as soon as you get into MR for his complete armor set because it has good survivability options like Health Boost and Speed Eating. Even if it's MR, Jagras is a punk.
For weapon specific progression, there is a channel on YouTube, RecommendedPlaying, that has Iceborne guides. Ignore the postgame stufff in those videos, since the most optimal progression after Shara is getting to Raging Brachy and partbreak farming him.
>Gameplay Progression and Tips
Don't be ashamed of carting. Money is the only thing you lose for it, and money is worthless during progression.
In general, the Bone tree has more raw damage than the Metal tree, but less sharpness.
Learn that monster's attack in flowcharts, and at the end of the flowchart sequence, there's a longer delay between its attack and the next sequence. In MR, this delay is super tight, and when you "see" the end of a sequence, you want to place the monster between you and your Palico and use the monster's turn to claw-clutch its head.
This is the time you want to learn clutch claw wallbanging, since the it deals flat+percentage damage. MR monster health totals are a slog if you don't regularly use wall bangs and the tenderizer mechanic.
Tenderizing a monster gives its parts a cracked appearance and means your attacks won't bounce off that part. What's more, the tenderized part always counts as a Weakness for any armor skills that give you boosts for hitting monster weaknesses. Barroth is the monster you'd want to practice this with since he has parts where lower sharpness weapons bounce.
The Hammer level 3 charge can combo into a tenderizer attack that also deals massive KO damage. Unfortunately, hammer is kind of boring since the most optimal play for it is level 3 charge and ledge jump attack head snipes.
Head shots, head shots, head shots. The more KO downs you get, the more raw damage you can pile on a monster. You can also focus on ONE of the monster's legs to get a trip knockdown, which is tracked separately from KO knockdowns.
Trapping monsters is faster than straight kills, and you can see when a monster is ready to capture by the number of slinger ammos it drops. After the third slinger drop, you can drop a shock trap and sleep bombs to clear the monster. People waffle about the rewards from trapping vs killing, but a majority of my playthrough was through trapping and I never had issues with progression. You can never trap Elders, though.