League of Legends (LoL) Question: Specific way to get fast IP?

With the 400 RP you get from getting lvl 3 you can buy skins that go on sale (skins that are normally 750RP go down to 375RP and skins that are normally 520RP go down to 250RP), IP boosts or icons (they're 250RP each).

I'll address your two questions as just that: 2 separate questions.

First question, concerning a fast way to get IP;

I've played League of Legends on over 6 accounts across my League career, and I've found this same problem, playing game after game and receiving minuscule IP.

One way I've gone about this problem was to purchase an RP boost (Which I'll talk about while addressing question 2), and another is to make a new account so that you can get more IP overall.

With this strategy, you can get 2 +150 IP win boosts a day, giving you more net IP over two accounts, but the drawback is that you must win a game on both accounts for this to activate and the IP is still spread about two accounts, in which you can't combine them together.

This strategy also has its' advantages, for when you're able to buy a champion of one price on one account, you'll be able to buy another champion at the same price on the other account.

I'd like to coin this term the "Buy one get one free IP champion sale", but you can call it anything you want to, as long as it works for you.

Second question, concerning what to do with the 400 RP given to you on a new account;

For my personal experiences, I've done a multitude of things with the RP given to me on one or more of my new accounts, some of which I will go over.

On my current account that I'm leveling, I bought a Cloud9 emblem to support my favorite team, and show off the icon to all of my friends, occasionally joking that they've recruited me.

I've also done other things with this IP, such as buy a 390RP skin such as White Mage Veigar, Golden Alistar, or Assassin Master Yi.
With the skin sales, you can also buy a 520RP or a 750RP skin on sale. (For a list of all skins and their prices, go here)

I have a friend who bought a champion with his RP given to him from a new account creation, he had bought Maokai while on sale, and he's been playing Maokai ever since.

It's a good way to add another champion to your pool, but I prefer buying a skin or a summoner icon, something that cannot be bought with IP (Just my personal preference).

OP, If you have any followup questions, please comment and I'll try to answer them ASAP.

Well, if you want to spend real money, then IP boosts are always nice. They give about the same amount as a first win of the day with every game. Granted, if you're going to spend money on IP boosts, you may as well just flat out buy the champion with that money.

Really, it is just a matter of playing the game. I've never grinned League particularly hard, and here I am with essentially everything purchasable for free in League. It just takes times.

For 400 rp, You can IP boosts so you can gain ip faster for 2 or 4 wins. The 4 win ip boost is
290 and the 2 win ip boost is 160. You can buy those in the shop,boosts.

Play this weekend with an IP boost active.
Double IP and the boost will make for some pretty fast gains

Probably play either aram or bots, coop interediate gives same as intro. i think.
you should probablynot spend the 400 rp. but if you're sure you're not going to but more, you can get the skins, or an ip boost. your choice.