Evens Are Better Than Odds!
In most of games, you start with some territories and 3 armies on each of them.
For example in a 1vs1 game in Classic map each players starts with 14 territories and 3 armies on each, from the experience that I have in playing real standard RISK game (Attacker has 3 dices and defender 2) always it's better to have even number of armies than odds, why? I will you give examples ...
Deploying:
Let's again think to a Classic 1vs1 game, it's your first turn, we have 14 territories with 3 armies and +4 for deploy, let's say we want to attack to a territory of enemy that for sure has 3 armies, if we deploy all 4 on 1 territory then we will have a 7, attacking with 3 dices to 2 dices has a "37.17%" chance of win double dices, so if we attack and lose double we will have 5 left and another attack with chance of "37.17%" winning double, but if we lose double again then we will have a 3 left that gives us only 2 dices for attack and it's a mistake to attack with 2 dices to 2 dices ...
But if in start we deploy 3 on 1 territory and 1 on another bordering territory, then we will have a 6 and a 4, this gives us 3 times of attacking with "3 dices", so if we be unlucky and lose doubles, this time we have 3 times of "37.17%" chance for winning doubles ...
Also when we lose a double on our 4 or 2 doubles on our 6 what is left is a 2 army territory that still has 2 dices for defending.
Reinforcing:
Another thing is when we are reinforcing, we have a lot of 3 territories, if we left them all 3, it is a mistake, because we can not attack with any of them as they have 2 dices for attack, and if we reinforce them all on 1 territory it's still wrong, because the enemy can attack a lot of easy 1's there and he will have "65.97%" chance to win any of them. the best thing to do is to leave 2 on bordering territories with enemy and fort the other 1s to somewhere for attack.
For example we have 2 territories with 3 armies, each bordering 2 territories of enemy that each of them has 3 armies too. if we reinforce 2 on another territory, we will have a 5 and a 1, we have only 1 chance of winning double, if we lose double we won't have any chance and we will have a 1 army territory that is so easy to take for enemy to get his card, or make us under 12 territories or so ...
But if we reinforce 1 on another territory, in attack we still have 1 chance of winning double, but in defense we have more chance to win.
I didn't count draw situations in this method, just double wins and double loses, not 1 win and 1 lose, but even if we want to count them, still in a 3 dices attack to 2 dices, as I said chance of double win is "37.17%", while chance of draw is "33.58%".
This is what I used and my experience showed me it works, what do you think? am I right?
Note: This is only for standard RISK games like this site that attacker has 3 dices and defender 2 dices, in other situations there may be better methods as I played some RISK games that give defender 3 dices or attacker 4 dices in some conditions.