Early Game :
Buy the following Heartseaker I, Hand of the Gods, 5 health pots.
Now do this. Go to the right lane and try to steal GREEN buff rom the enemy (usualy they won't susspect it since
everyone starts at blue). But if you feel that you are able to steal the BLUE buff than go ahead. Odin is very TANKY by himself so you can be quite aggresive with him. And stealing the buffs (do that ONLY after you push your lane so you don't loose minion exp and gold while going to a buff camp) will give you XP and GOLD advantage over the enemy. If everything will go as planned finish the Hearseaker III, next you want to get Warriot Tabi III. By the time you finish your boots you should have 40 stacks. Now we are in Mid Game.
Mid game :
Now you are strong enough to kill people alone, focus down enemy mages and try to avoid enemies like Bakasura or other strong AD gods since you are not strong enough to face them ONE on ONE yet. Engage in team fights and stay with your team. Farm up that gold for your next item which is Frostbound Hammer III.
That item is your most important item since it let's you chase enemies down to infinity. But remeber to NEVER use your ULTIMATE in teamfights since it will usualy cause more harm than good, I will write down how to use his ultimate in the tips below. And so the Late Game begins.
Late Game :
Here is where your dominion begins since your damage will mostly come from auto atacks and your third skill is mostly used just for the additional slow and your seccond skill takes priority since the atack speed buff makes you tear people apart. Buy your Executioner III and the rest of the items if you have enough gold, but usualy at this point the game should be already over. No other god can stand before you and hope to survive if they try to fight you, not even Bakasura.
Use your ultimate during the laning phase to trap enemies insite WITH your minions for additional damage and AFTER casting your ultimate cast your third skill to apply massive damage and a slow so a couple of auto atacks go in. Also you should use it primarly in 1 v 1 situations since it gives you a big boost to damage and protection. Also don't waste your ultimates on gods that have JUMPS because they can just jump out of it, unless you saw them just waste their jump on something. Also remeber that if you miss your ultimate or trap your team in it, quickly press 4 (or other button that you have your ultimate on) to bring the spears down prematurely.
Early Skill focus is on skills 3 and 1 because they do a LOT of damage if landed and you don't do enough atack damage early. Remeber there is quite a big delay on your skill 3.
Skill 2 in mid/late game is your biggest asset since it can melt down towers with minions in secconds, and increased your DPS(damage per seccond) a LOT in late game.
In a 1 v 1 scenario your skill activation should be as follows : 4 - 3 - 2, 1 (jump) should be used to chase the enemy down IF he was able to survive during your ultimate. Also remeber to not ultimate gods that have a jump as I mentioned before.
And a tip about fighting bakasura in late game. When facing him 1 v 1, wait till he uses his ultimate or his burning blades. Just kite him (run arround at safe distance) and wait till his true damage buff ends. After that start OWNING him, if he jumps away, jump after him (unless he jumped to allies) use your ultimate, slow him with gungmirs might and activate the speed buff and send baka to where he belongs, before your knees.
One last OBVIOUS tip. If the enemy team has a lot of disables buy Purification Beads. (your ultimate makes you immune to disables BUT you cannot always use your ultimate)
Now go out there and show them the might of the Allfather !!!