Welcome to my Guide on using Fates and Fortunes. First of all what are Fates/Fortunes? These are basically abilitys that have a "Persistent Effect" or are "Interventions". Persistant effect will start the game active and remain active until the end of the game while Interventions cab be activated at short notice to give a small boost to combat or the die.

Now i class Fates/Fortunes in 4 catagorys "Big Spender", "Investments", "Insurance" and"Pocket Change"
Big Spenders are any Fate/Fortune that is of 100pts or more while the rest apply to the cost as it goes down. (Insurance is abilitys that cost 50pts for example)
How do i know what are worth taking and what are not. I'm going to go though what i think are worth a consideration and waht never to use for both forces and give my resons why. Remeber this is jsut my opion.

"Big Spenders"
Fortunes
Athelas is a very useful ability allowing you to bring back to life any Epic hero however it comes at a cost of having 0 Might and 1 Resiance which means they don't like duels. However i feel that combined with the "Desperate Actions" Fortune it is a must. However i beive that this abiltiy if useless in any army that isn't in a army of atleast 2000pts.
Orcbane/Trollbane are both very useful however both are sutiational which means you really need to knwo what your opponent is goign to do in order to use them. Trollbane is way to riskly to take in my opion but Orcbane is often worth a look as 3 out of 5 armys can(And often do) use orcs.
Steeds of Pure Blood gives a really good boost to cavaly giving the unit a move of 14". This upgread is obviouly less useful to Sons of Eorl or Galaldhrim Knights who are fast to start with. If you using Rohan and maybe Gondor concider this along with the extra spped it grants.
Fates
Morgul Blades are billant giving the unit a wound on a 4+ rantehr than a normal 6. I have used this fate on a group of Goblins and it really cut down to size Gobdorians or Dwarves. If you can spear the points invest in this dark blade but the high cost can put many off.
Dwarfbane again it risky even more so than Trollbane and Orcbane as many evil ares use them. Only ever use this if you know what your up agaisnt.

"Investments"
Fortunes
Galadrim Bows are realy useful for units that are week at range or for amking others really strong (Outriders ofEored become shoot value of 1!) however never give it to people like Haldirs elves as it is wastedwith them thanks to "Take Aim". I would suggest it if playing defencivly but otherwise ignore it. It's a little too expencise.
Untainted Palantir/Tainted Palantir both do the sem thing so i'm putting them together. This allows you to add 1 to priorty rolls however having priorty is not always good and if your oppoent take one too them it is wasted points. This is a very much personal prefrance.
Fates
Cursed Armour of Udun is really good giving a +1 defence bonus to anyone equiped with it however think carfuly on who you give it too. Do you protect those vunrable archers or to beef out your dfence 7 Monaraon orcs.

"Insurance"
Fortunes
Desperate heroics is fantastic ability. Immagine a Boromir who has no might left. Take away that last point oif might from a captain and Boromoir now has all 6 might left. If you have Boromoir i would recomend taking this forunte.
Blessing of Galadriel is a favoutie amoung most giving you D3 more might which is really useful for people lik Dain, Legolas extra. If you feel you need that extra might on 1 hero then take it instead of a captain.
Army Banners are in my opion useless. They give you a nice new ability of Heroic Advance but i have never once ever been able to use it. Ignour this ability as i find it pointless.
Fates
Crown of Carn Dum is a risky pices of equipment as it can give you a 50-50 chance of free might but can kill you in a second you you roll badly however monsters like the Balrog and Dragon like it as all that happens is that rolls on the wound table giving it another 50-50 chance of avoiding the side effects. Think caruflly before taking this crown as this one has thorns(And there is the bad joke)
There will be No Dawn is fantastic to avoid the enemy gettign chargs in essicialy if most of your amy causes terror. If you have lots of Terro units then concider this but wherether you would like itm othersie it's hard to say.
Tormented Stteds gives a +1 stength to any Evil Cavalry which is really good when you give it to Warg Riders or Morgul knigths who have high strength and lances. If you ahve good cavalry conider it other wise ignor it.

"Pocket Change"
Fortunes
There really anything that is worth note for Good here it a question of what you want really which is dispointing as this catagory is the most ly to be used in battle.
Fates
Balefire Arrows are a very good investment giving you a drive back roll even if you only kill 1 man. They also are a must agaisnt any ents. If you have only 1 main archer unit given them this. Also take this if you expect Ents.
Black-hearted Trees are an Elves worst nightmare as this forces them to think about hiding in terrain otherwise risk D6+4 strength 10 hits. Owch. I love this ability and if Balefire Arrows don't suit you then take the trees.

I hope this has helped you all look at Fates and Fortunes(And i hope you where able to stay awake though my rant)
Take care and enjoy you life