(standard) GBW Xenagos help and feedback please?

I think this is a pretty sweet rough draft somewhat similar to the Tier 1 Jund Monsters deck except in Naya colors and about half the price.  You mentioned you're trying to use cards from your inventory to improve it and build a sideboard.

First, I notice you have a Chandra, Pyromaster in your inventory that card needs to be in your 75.  It's a beast with Courser of Kruphix.  You may even want to mainboard it by swapping it in for a Lightning Strike this will round out your curve to 8 total 4 drop threats. 

Second, I think you're a bit light on mana for your top end threats of XenaGod and Elspeth. Jund Monsters gets away with 23 land and 2 of them being Mutavault because it plays 7-8 accelerator creatures with both Elvish Mystic and Sylvan Caryatid.  I'd cut the 2 Hornet Nest and add a Stomping Ground and another Caryatid.  This will help your base be more solid and help you cast your Courser, Polukranos, Phoenix, Xenagod Planeswalker, or Chandra on time.

Also, there may be too many temples basic land which could/should be shocklands to help you cast things on time.

Boros Charm needs to be in this deck.  They're a little expensive for an uncommon ($1.50-$2.00) but they do a ton for your gameplan: saving your team against Supreme Verdict or Planar Cleansing, double-striking for one of your big guys, or just 4 damage to your opponent's dome as a finisher.  Get em and a find a spot for them if you can. 

There is no reason to have 4 Bow of Nylea in the 75.  This should be a 1 of in the sideboard at most in my opinion.  Good to bring in against Mono-Blue Devotion and some other aggro-decks. 

You don't have a Domri Rade, so I won't go there, Elspeth maybe a little too ambitious and somewhat against your big monster strategy with her -3 is going to hit your game winners of Stormbreath Dragon and Polukranos. 

Lastly you probably want some Ghor-Clan Rampager to push through damage especially with Polukranos.  For as bad as a XenaGod trigger on a Polukranos for a 10/10 hasty hydra may seem it still gets chump blocked by a 1/1 token.

If I have time later I'll copy your list and make some mods and post it to see what you think.

How did you do at your FNM/Gameday after the changes? 

What cards seemed to work or be relevant every time you drew them and what cards seemed to be useless and sit in your hand? 

Did you have any cards that you really wanted to cast but couldn't because of mana colors being wrong?

I've copied your deck, and am modifying it how I think I might do it without adding a bunch of really expensive cards.

Let me know how you did.

No offense but I think you are looking at Chandra, Pyromaster the wrong way. Chandra's +1 is a utility to kill 1 toughness creatures or to prevent your opponent's biggest dude from blocking, her real value is her 0 ability.  This is basically a free card draw every turn, which is liquid gold.  If you don't need it don't cast it and it gets lost but now you are one card closer to the card you do need. 

Don't give up on Chandra as a mainboard card yet.  Think about how you're using her.  If she's out on the board use her 0 ability before you play a land or cast any other spells. You may exile a land, or Stormbreath Dragon.