sageoftruth said:
I'm quite the Magic the Gathering noob myself. What is a mana curve? I'm guessing it has something to do with basing the number of lands you should have, on the costs of your spells and summons?
That's part of it. It's the number of cards you have in your deck and their associated mana costs. It's easier to show someone, but as an example, in a 60 card deck you generally want around a third to be land, which equates to around 24 land cards. However, depending on the number of high/low cost cards you have this can change. So the best thing to do is lay out all the cards so that your 1 mana spells are in 1 row, your 2 mana spells in another, and so on, so that you can easily see how many of each cost you have in the deck. Ideally, you want the deck to "curve", with maybe a few 1 drops, then slightly more 2 drops, peaking at around 3-4, then having fewer 5 and 6 drops. This shows you where the bulk of your cards fall on your deck, and assuming you draw consistently well, how likely you are to be able to play creatures or other spells on each subsequent turn.
What you don't usually want is, for example, a deck with 12+ 6 mana creatures, and only like 4 2-3 mana creatures, because you'll likely end up with all these expensive cards in your hand way too much and have nothing to cast for the first 5 turns.
This then impacts the amount of land you run. If your curve is quite low, say for example it has nothing above 4 mana, then you don't need as many lands because you'll start drawing too many as the game drags on and each additional land you draw probably doesn't help you, whereas if you have quite a few more higher cost cards, then you'll need to add a few more lands, to ensure you consistently draw lands and can play these cards out on curve.
Of course, you also then need the right ratio of mana of whatever colours your deck is running as well, so whilst your deck is laid out this way you can easily count the mana symbols in the costs and compare how many there are of each. Also bear in mind cards that cost double or more of a certain colour, and where on the curve these colours are. It might be that most of your 1-3 mana cards only require a single red mana, but late game your 4+ cards might require double green, which is going to require you upping the number of forests, with the problem being that the more forests you add, the more likely you draw them early, where they aren't as needed. Having a balance of colours and not getting greedy is a must.
This is all just general ideas of course. Depending on the format you're playing or the strategy your deck is based around can wildly affect your curve. My modern deck for example has only 18 lands and nothing above 3 mana, despite being 3 colours, due to the excellent colour fixing available, but my edh decks, being 100 card singleton decks, all have 30+ lands, and some, like my [mtg_card= Animar, Soul of Elements] runs about 40 creatures, with many of them triple green 6 or more costs. In sealed you generally run a 40 card deck, due to having a much more limited number of semi-random cards, and there you typically run 17 lands, only varing by +/- 1 if you're an aggressive deck or not.
There are people who can explain much better than me though, and with visual aids. Youtube can probably help you more.