Firstly, don't be discouraged if at the start of the game you are having difficulty due to it seeming like everything is much stronger than you, because simply,
they are.

The game is balanced around the idea you will be using cheat tackle at least once a battle, this is why most strong trainers have an "ace" at the end or just one very strong Yarimon. This can make early game seem very difficult at first due to most opponent's strong Yarimon being able to one shot your own.
There are a few things you can do in the beginning to make your progression easier though. Firstly, status effects will be your best friends, unlike Pokemon where they are pretty meh, in this game blaze is an insane status allowing you to take down Yarimon significantly above your level granted you can survive.
My first recommendation would be to go catch a female Guardog, they are very easy to come by as all you have to do is follow the road of beginnings all the way up north and then continue through the only pathway that keeps you going north. You are then able to find and catch one in the very first patch of grass on the left.
This is because they learn at a very low level the move P-Kinesis, which allows for a guaranteed blaze application on the enemy, this is incredibly valuable as it allows you to take on pretty much any enemy that doesn't instantly one shot you. This of course doesn't help very much against enemies that do one shot you, but it allows you to take on relative to your own level significantly easier. Through doing that you can slowly build up your own level by taking on stronger and stronger trainers as you level up yourself.

Your other Yarimon is more personal preference, you can go for another blaze applier, or curse which is a slightly worse blaze as it doesn't decrease defense but instead prevents healing while still doing damage over time similar to blaze. Personally, I went for Klaydirt, as even before, but especially after he evolves, he is incredibly tanky, having a move that heals 50% hp every two turns, allowing for the blaze to do it's work.

Luckily, after the early game, you can just turn your brain off, as with two specific Yarimon and a little rng, you can win every battle with very little problems. Anyone who's beaten the game before likely knows the two I'm referring to, Moostar and Soliche.
IIIIIIIIIIIIIIt's comical how easy these two make literally every fight in the game. Moostar gets access to a fun move called Zen Mind, it has a two turn cooldown and raises it's own evasion by two, on it's own it's pretty simple, but the thing that really allows it to make the game trivial is when you combine it with Moostar's ability Beguiling Light. You might be wondering what it does and lucky for you I'm here to tell you. Beguiling Light is an ability that makes it so whenever an opponent's attack misses it, it does 50% of their MAX HP. I'm sure I don't need to tell you why that's insane, especially on a Yarimon that has a natural evasion increasing move. Put Moostar in the front of your party, buff up your evasion a little bit and watch as the opponents team disintegrates. The only downside is that you might need to rely on a little bit of rng for that first and second turn evade if your opponent is significantly higher leveled than you. If they aren't though taking hits is fine since once you've used Zen Mind twice you're pretty much set, although you should always go for the max of four times if you can.
Moostar can be found pretty much immediately once you leave the Village of Beginnings, the only reason I don't recommend it early game is it is level 50, so it could be a little hard to catch immediately. You could definitely catch it then using blaze however if you so desire. Moostar can be found in Harbor town in a small cave on the bottom left beach of harbor town. Once you enter the cave you will see it dive into a patch of grass where you can catch it.
Assuming you've been paying attention though, you might be asking "What happens if Moostar gets hit with a status effect, those aren't attacks?" And you would be right, but this is where the second Yarimon, Soliche comes in. Soliche's passive ability, Solar Radiation, makes it so whenever he enters the field the enemy is inflicted with Blaze. This is obviously good as it makes it so you don't need to worry about higher level Yarimon one-shotting you before the blaze can be applied, as it's just done upon entry. The Blaze's defense decreasing ability along with Soliche's ridiculously high attack stat and the fact flame moves are just stupidly good make it able to easily shred through yarimon even a higher level than you, granted they make it through Moostar. Unlike Moostar, Soliche isn't available right away, but becomes available around the time you visit the Central building for the first time. He can be found by taking the small path at the top of the Road of beginnings to the right, leading into a fiery cave. It's initially blocked off by another trainer but when you progress through the story she moves out of the way.
This strategy allowed me to beat the entire game and end content tour quite easily, the only trainers who gave me any trouble at all were the very first few difficult early game ones and then a few status effect applying ones. If you need any clarification or you need any specific help just leave a comment and I'll be happy to help out.