I'm 15 hours in, I have played the main story mission in the Draken Hold and can't beat it, I've tried the other rout with the evles but the battles became failures.i messed up my formations and battle commands, if there anyone who can give me tips? I wanna get bavk into this game, I love it very much but I just can't seem to make parties work to overcome these long battles. I left the game for too long and messed up everything experimenting before I put it on hold for Khazan. I don't wanna play 15+ hours again.

Please and thank you in advance. 

This game has endless tactical routes, and I haven't played it in a while so not sure if I can help. Are you under-leveled?

Is there a way to level? I found no method. 

Did you not recruit the character Selvie yet?

Its possible you are underleveled, but to be honest unless you are playing in the highest difficulty you shouldnt struggle too much with it - To do replayable scenarios and level up your squads you gotta recruit Sylvie near the bottom right of the Cornia map. After you recruit her you gotta pay attention to the circle formations (like the one next to her when you recruit her) to unlock replayable scenarios of higher level.

Other than that: Farm honor. Honor is important specially in the early moments of the game, you need it to unlock more unit space in the squads, upgrade their classes and unlock more squads. To farm honor the easiest way is to farm the replayable scenarios I just described earlier. Another method is doing town deliveries, you should be leaving guard in 100% of the towns, that way you collect items to do these deliveries.

Keep in mind that unlocking unit space will be more important than upgrading units. Having 4 ~ 5 units per squad is a huge diference maker, and at the point of the game you are, it makes it easier to overwhelm enemy squads.

Other than that all I can tell you is be mindful of your formations, dont put fragile units in the front and dont send a squad with a type-disadvantage to attack another. Like, dont send a squad full of cavarly to attack dragons or gryphon units.

Assuming you are playing on normal, stock up on items and abuse them as much as you can. By your long battles comment I can tell that you have problems keeping them alive which can be easily fixed with some revival orbs. Also, garrisoning units in towns and forts heals them and revives the fallen units.

I am a bit surprised that you are having trouble as I put it on expert by mistake for my first completely blind playthrough and only realized my mistake after having beaten more than half the game, as I was finding it only mildly challenging.

Thanks people. Yes, I'm indeed underdeveled and with your comments I now assume even being recommended level may nit be viable with this style of game so I will unlock this character that allows for leveling and get two or three levels higher than recommended. I also have not outfitted everyone in the units with proper gear, only the leaders, something I wasn't thinking baiut cause ai was wrecking everything in the early game and didn't see the need. I've almost gave them all upgraded fear but wiped myself on money and hopefully that resource will vome while grinding in whatever form this character unlock allows cause I have left myself with no healing items. 

Yeah, that's really annoying, experimenting and adding in characters to test them and swapping out again has left me crippled as well as using my main two units in almost every battle. Some characters are less than half of where they need to be as to why they are getting one shot and that leaves me with no option than to replace them with higher level characters despite how I want a unit to be formed. Not going to enjoy leveling in this game, I would think, gearing out everyone has little effect and Selvies missions are hard to come by. Such bad balance for such a great game, might drop to easy but knowing this scenario it'll be too easy and ruin the game in another way, God I hate difficulty options, they are the Plague of gaming and never balanced to my needs.

Didnt need to level. I missed the top half of the vorbia Mao which I thought was higher level than Drakenhold and The Elf lands, a lot of great characters that come pre leveled and I can now promote with the renown level B, everything is back to being decimated now and the Another Prince mission was easy.