I'm playing on Challenging so please take that into account. Maybe you should decrease overall difficulty of your game for start.
Also, my advice would be to reduce the monster frequency to "Moderate" and not have it on "Dense" if you do.
Other than that, your faction traits will influence what research and expansion strategy you should use, but let me give you some general advices that should help you in your gameplay. I'm always playing custom factions, by the way, and mostly Kingdoms.
1. Try to use two armies to farm monster XP - one with your sovereign, the other with your first hero who you can recruit at turn 1-2.
2. when you found your first town, build 1-2 Pioneers first and with them try to settle one more town (1. pioneer) and get some resources capped (2.pioneer). Use the safest locations you can see, which is to say don't settle on the location which has a big monster lair in vicinity.
3. Go with starting economy techs, then switch either to magic or warfare (also depending on your faction). You need one or the other to compete with the AI, and fast. You need some defending troops against monsters and for your first war.
4. When you encounter other sovereigns, take a look at the faction strength. If they are a lot stronger than you, expect a war soon. Especially if they're of the opposite faction (if they are Empire to your Kingdom). So start preparing (warfare tech as far as you can without spending too much time). By that time you should have ~3 cities, focusing on building them up and helping you research.
5. Don't despair when the war starts and you see Juggernauts coming your way . See what the enemy has and try to counter. Generally, I'd advise to (unit wise) be prepared for war with researched mages, unless you're playing Yithril or Magnar. They are not expensive (except crystal) and can help you against heavily armored enemies. I found that I'm behind AI with warfare tactics pretty long and then you need magic to compete.
6. Choose your battles wisely, especially against monsters. Bears with maul could be your end at the start, and don't tackle big monsters (unless you have to) before you're ready for them.
Many things are decided by luck - if you have chokepoints, enough time without a war to buildup, enough easy monsters to farm XP and at the same time no big monsters to wreck your ciites -> some or all of those things can improve your chances.
I guess other people will have more useful advice for you, but this is a start.