Hmm OK.

Step 1 is to pick a Faction that you enjoy playing, with or without a custom Sovereign.

Step 2 is to start the game and look for a good starting city site, I hope for a 4-3-2 next to water or forest or both.  You can press Control-N repeatedly until something like this shows up, or you can ironman it and hunt around for something else adequate nearby.  You want to be next to a forest for more production (Logging Camp etc) or water for more longterm gold and food (Docks etc).  If the city site is good enough don't worry about it, but that's the goal.

Step 3 is to cast some strategic buffs on your city.  Enchanted Hammers (Earth), Meditation (Generic), Oppression (Death) and Inspiration (Water) are all fantastic early game city buffs.  Most of the rest are pointless early on as they relate to buffing created units and we are not doing that immediately.  As part of this process take a look at the nearby recruitable hero and what buffs they have to offer for your city.

Step 4 is to lower your tax rate to none.  This drops your Empire-wide unrest rate to 10%, so the peasants are happier while constructing your towns.  I find the early game is not in need of much $$$, unless you're rushing a lot of buildings, and so I tend to run on zero taxes until I have some unrest-reducing buildings (Bell Tower / Shrine) created.

Step 5 is to set your research.  Unless I am playing a Sov with the wealthy trait I always tend to research Restoration first so that I gain access to the Workshop improvement, then I get Civics.  My next step is usually Training to get some basic spearmen.

Step 6 is to carefully explore nearby with your Sovereign and Hero in two separate stacks.  Pick up free stuff, kill small monsters, try to find out what is nearby without dying.  If you get your hero / Sov killed don't sweat it, just be more careful in the future.  You will find some stuff nearby which is too big for a hero to solo, make a note of those spots and come back when you're bigger and/or have some spearmen/sand golem/whatever to assist you.  Try to expand where it's safe, and build spearmen to force the issue as necessary.

That should get you started down the road to ultimate victory!  Now a few of your more specific questions:

1. Generic gameplay tips
1. Try to get started on the long-term accumulation resources as soon as possible.  Crystal takes forever to reach critical mass, so I tend to prioritize it more than metal.  Get shrines as soon as practical, but unless I am using tons of mana I go for crystal before shrines. 
2. Remember your cities will experience severe unrest unless they are connected in your Zone of Control (ZoC).  Get the new villages started asap with pioneers, but don't forget to build more of them for outposts to connect everything together.
2. Bows.  Ranged weapons are not terrible, but they need support.  If you have a heavy melee unit or three to keep people away from the ranged guys then they can be very strong.  That being said crystal-based mages are superior to bowmen against heavy-defense targets as their fire/ice damage bypasses normal defenses and targets fire/cold resist instead.  If your target has no fire/cold resist you hit for full dmg. 
1. Extra caveat - if you have a fire mage (even a teeny one) you have access to a city buff called Heart of Fire.  It's expensive to cast (100m) but units constructed in that town gain +1 fire attack (added to their base melee or ranged) per essence the city has.  This means if your city has 2 essence then basic bowmen will have 7 physical attack supplemented by 2 fire, for a net improvement of +28% DPS from just that one spell.  There are other city buffs like this as well for defense, health, initiative so keep them in mind when producing units.
3. Must have techs?  You need workshops, you need bell towers, and IMO you need trading so you get roads between your cities.  After that go with what looks appropriate at the time.  As you get more of the unrest-reducing techs built you can raise your tax rate, which then gives gildar for recruiting more heroes and rushing buildings so I feel that to be pretty important.
4. Summons summons.  Starting with a summoning mage helps the early game significantly.  It's a huge boost to get a pretty strong free unit to help kill the mites and darklings.  Late game the Fire and Earth elementals are pretty damn strong tanks for your army and if they die you can just summon a new one for the next battle.  I never liked water elementals much, but they are OK and do have their uses.  If you CAN summon something, you should definitely DO SO, assuming the turn by turn mana cost is doable for you.  The only two mages with the summoning trait (Warg, +2 levels on summons) are Ceresa and Procipinee, neither of which will ever get Fire/Earth elementals.  Yea it's possible to buy the fire books w Proc, or sacrifice some poor sap to gain knowledge, but the reality is those are unlikely to happen in time for you to skill up Fire/Earth.  However all the Summoner trait does is provide +2 levels, which boils down to about +10 HP, +2 accuracy and +2 spell resistance.  So once again I reiterate, if you CAN summon something then DO SO.

I hope this helps. 

THANKS SO MUCH!

such a detailed and useful post

i will be using these tips for my next run surely

Other tips:

Be careful with the settings, they might change the general game process very much.

You can change the maximum map size by yourself or download mod that changes it (ecomental map for exemple, there is another one that is also good, i don't remember the name.)

Build order in your city should look something like the following -

exploit nearby resources, (shards, orchards, farms, mines etc) there are usually 1 or 2 of those, Resources would include pier's for river sites and logging camp for forest.

next you will want a pioneer (by then you should have scouted a suitable second city location.)

Third you will want a production enhancing building (workshop or similar) 

then you will either need a second pioneer for a 3rd city or a spearman to start strengthening your sov's army.

after that it really depends on the game. 

Im sad to say this, but i just won my first easy game handily and am happy about it.

Thing is, it wasnt even funny how easy it was. I had more cities than the other 2 factions combined times 2, and one squad of 6 was enough to beat all their armies and sack all their cities

going to try normal, then hard now

just what i did from the above tips

1. i used tarth. seems to be a good newb race. being immune to random monsters is great for settling everywhere

2. a pioneer should definitely be in the first 1-3 things you build, i made it my first, even if you have no good prospects, make em

3. rush to 3-4 cities, let the new cities make pioneers if need be. settle these as a good base (no pun intended). 4 lousy cities early is better than 1-2 beefy cities early

4. do not fuse your early champions to be safer and stomp enemies. send the sovereign one way, the 1st champ the other. better for xp, and more loot. refuse them when you have 3-4 decent locations and the baddies become too tough (my big mistake before)

5. farm the random mobs, getting to level 3-4 early is great

6. full cast all city boons whenever you get a city (another big mistake i made before, neglected to constantly use magic)

7. Use spells, summon, weaken, boost, whatever. i used to let my mana stockpile and bring it out in war. no reason not to have summoned beasts, beefy cities, and augmented champs

8. Ignore warfare tech for the first few techs, heroes are more than enough at first

9. Set taxes to none (Thanks for this). money in this game really only used to rush buildings and hire champs. its a big boost early on to pump production while there are no real wages to pay

10. Probably one of the biggest things i learned, the relative unit strength meter is highly innacurate. When i went to war, many enemy units were marked as "strong" while mine weak or moderate. won most battles without losses. best i can say is study how you handle different enemies, and if you see an army of something you have been steamrolling marked epic. just steamroll some more