This Following Deck is an elf deck. It is basically a swarm deck, where i get out alot of small elves to power up the bigger ones, then use wellwisher to gain extra life.

 

18 Forest

2 Coat of Arms

1 Elvish Vanguard

2 Elvish Champion

1 Ambush Commander

4 Wellwisher

1 Rushwood Elemental

1 Voice of the Woods

4 Timberwatch Elf

4 Heedless One

1 Wing Snare

1 Moment's Peace

4 Norwood Ranger

2 Elvish Warrior

2 Elvish Pioneer

2 Wirewood Herald

4 Defiant Elf

 

I faced a couple people, and i got demolished, one of them was a land destroyer, and the other one was a flying deck. What could I do to Power this deck up?

Ah, an Elf deck.  I've never played an Elf deck personally, but I have seen quite a few of them close up, working their magic...back when I was starting out.....that guy's Elf deck....could never beat it......the pain....the trauma.......no...not the Stonewood Invoker.............

 

 

Okay, I'm back.  Sorry about that.  Where was I?  Ah yes.  Now, the strengths of an Elf deck are that it floods the table with Elves, it can produce massive amounts of mana, and that almost every Elf has an ability that benefits other Elves.  Frankly, most Elf decks don't really need any non-Elf spells except to be the finishing move.

Now, you said you lost to a land destruction deck.  That's the first signal that something's wrong here.  By the time a LD deck can cast Stone Rain, you should barely need lands anymore because lots of Elves have mana abilities.  Replace Norwood Ranger with Llanowar Elves(the early mana is far superior to the extra point of toughness, and will continue to be relevant long after the Ranger would've chump blocked and died).  And replace Elvish Pioneer with Silhana Starfletcher.  It produces mana and can block fliers, which brings me to the next point.

You also mentioned that you have trouble with flying decks.  This is a bit more understandable for an Elf deck, but can also be overcome.  Green has plenty of anti-flying tech, much of it better than Wing Snare.  I recommend Tel-Jilad Archers and Elvish Skysweeper, because in the event that your opponent doesn't have fliers, it's at least another Elf.  As for what to take out, I'd say Ambush Commander and Voice of the Woods, since five mana for a 2/2 Elf is most likely the reason that you lost to that LD deck.

One more thing I want to make room for is Silhana Ledgewalker.  This little Elf has made a big impact since Guildpact was released, and she's absolutely head-over-heels in love with Timberwatch Elf.  When these two are on the field together, the Ledgewalker can carry Timberwatch across the threshold, right into your opponent's face.  Ideally, they'll want the family there to attend the wedding, but just the two of them is nice too.  I'd say take out the Defiant Elf for the Ledgewalker, since going unblocked is better than trampling over a blocker.

And finally, replace one Forest with a Wirewood Lodge.  It won't really help much against land destroyers, but it will help against everything else.  And replace that Moment's Peace with another Elvish Champion, cause you really need to get two out to start having some real fun.

 

So, in summary: