When Richard Garfield created Magic, he gave it five colors, and gave each color its own play style-- things it can and can not do. Magic has continued that tradition to this very day, and while the exact set of abiltiies each color lays claim to has shifted a bit over the years, all the core tenets are still as they were in Alpha.
 
What that means is that if you build a monocolor deck, the color you pick determines a lot about what your deck will look like, and two monocolor decks of the same color may end up handling similarly despite completely different decklists.
 
Today's deck is a mono-green deck. Just by saying that, you know that it's going to be creature-heavy, have mana acceleration, and ramp out some big, beefy hitters who will then swing for the win. There won't be very many ways to kill opponents' creatures beyond forcing them to chump block or blocking and pumping your blocker, and whatever instants, sorceries, or enchantments the deck has will enhance your creatures or your lands, or both. 

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Hey I was wondering if you could help me with this deck. I'm fairly new to Magic and I'm trying to build a Mono Green deck around Protean Hydra. I'm also on a budget, a few people have recommended Primeval Titan but I just can't afford stuff like that. Anyway here's the deck.
 
4 Llanowar Elves
4 Arbor Elves
4 Nest Invader
4 Protean Hydra
2 Bellowing Tanglewurm
2 Engulfing Slagwurm
 
4 Canopy Cover
 
4 Cultivate
4 Harrow
4 Vines of Vastwood
4 Giant Growth
 
20 Forest
 
So the Llanowar Elves and Nest Invader generate mana. I continue to untap my lands with the Arbor Elves and search them out via Cultivate and Harrow. The Canopy Covers, and the pump cards can be used in case I get into a tight spot or just to help finish the game. Bellowing Tanglewurm adds intimidate for my creatures and Slagwurm can pretty much destroy anything. Basically I want the deck to generate mana fast and swarm the field. Can you help a new guy out? Any advice is appreciated, thanks.
 
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This deck plays out just as I suspected it would from the title. The names and cards change, but the strategy remains the same. And it remains one of my favorite monocolor strategies. So, having played it myself so often, I think I can indeed help you make it run more smoothly.
 
As you may have already noticed, enhancing your mana means you end up playing all the spells in your hand faster, which means you may run out of cards in hand once the big dudes hit the table. Which means, if your opponent has a kill spell for them, you may find yourself out of options. The solution? Extra card draw, to keep your hand stocked and ensure that if your first Hydra bites it, you have another Green Beast waiting in the dugout and ready to pinch hit. This is why Green/Blue is my favorite combo. Green ramps mana and drops massive dudes, and blue refills the hand, gives the big dudes flying, and bounces blockers off the field so the Green Monsters can get through. But you're not running blue, so you'll need some Green-style card draw.
 
Unfortunately, most green draw spells lack the sheer drawing power of Blue's options. Most of them are just cantrips-- cards that draw you a single card, which simply means they replace themselves. Fortunately, most of green's draw options do other things besides draw, and all the things they do are things you'd like to do.
 
At the simplest, there's Explore. You draw a card, and are allowed to drop one extra land this turn. This isn't always great if you don't have an extra land in hand, but Cultivate improves your odds, and you can draw a land off the Explore and drop it. If you don't draw a land with Explore, then you can just pretend Explore has Cycling 1G? Explore is still better at ramping mana than Nest Invader-- the Eldrazi Spawn is only good once, while the extra lands stays in play and taps for mana every turn. I'd switch out Nest Invader for Explore, unless you really think the 2/2 body is important.
 
Next is Snake Umbra, which serves a similar purpose as Canopy Cover-- an extra layer of defense for that Green Monster you just payed all that mana for and don't want to lose to a Doom Blade. But Snake Umbra also lets you draw a card whenever its wearer connects for damage. Bellowing Tanglewurm stands a better chance of getting through than the Hydra or the Slagwurm (the Slagwurm's ability destroys the blocker, but the Slagwurm is still "blocked" and so it's damage doesn't go through), but if you had a creature with Trample, that'd be a great choice. Only a single point needs to push through for you to claim that card!
 
And if you want a creature with Trample, might I suggest Pelakka Wurm? Another of Green's card-drawing options, and of course, it's a big trampling creature. Pelakka Wurm makes a great win condition, because if your opponent manages to kill it, you get to draw a card. And really, that's the whole reason we wanted to draw cards, right? To replace our fallen predators? And of course, that 7 life you get for casting the Wurm in the first place is nothing to scoff at, either.
 
You don't need a lot of card draw in this deck, just enough to grease the wheels and help keep the ball rolling. If you're going to generate all that mana, after all, you'll want a hand full of cards to spend it on, right?
 
The other thing this deck really ought to have, but doesn't because most monogreen decks don't, is a way to deal with opposing creatures. Usually, the only reason a green deck cares about its opponent's creatures is if they're blocking your creatures, in which case the answer is to just have bigger creatures. But opposing flyers can be a hassle, since you can't block them and they don't block you. Utility creatures, like tappers, pingers, and anything that's more meddlesome because of its ability than its power or toughness, can also be a quandary to dispose of. My solution? Well, if you have these kinds of problems, I recommend you take a closer look at Irresistible Prey. For one, it also draws you a card. More importantly, it has two main uses. Play it targeting your big guys, especially Engulfing Slaguwrm, and your opponent will have to throw somebody under the bus. I recommend this tactic the turn after they play their little dude with the activated ability that requires it to tap. Normally the tapping guy could stay out of combat by using its ability and thus being too tapped to block, but if it has summoning sickness, it has no excuse to ignore the Irresistible Prey, and gets creamed. The other main use for Irresistible Prey is a sort of small-scale Lure. If your opponent left a single Wall of Omens to hold off your Hydra, play Irresistible Prey on an Elf and swing with the Elf alongside your powerhouses. At least one blocker will have to tango with the Elf, which may be a problem if your opponent only though he'd need one blocker that turn. Irresistible Prey is a niche card, I admit, but if you have trouble getting the combat phase to go your way, it can really throw a spanner into your opponent's battle tactics, putting them off-balance and leaving you an avenue to victory.
 
Good luck!
 
~BMoor