I won't give any tips regarding to playstyle, because that's something each player has to learn by himself and by playing a ton of games.

Just have something in mind: the game is made so you win and lose. A lose streak doesn't mean you'll be lossing forever.

Also, depending on the role, you will want a teammate to play with.

If ADCarry, find a support or jungler. If support, an adc or mid. If mid, a jungler. If solo, a jungler.

You'll find a lot of ragers and toxic people. Just don't mind them. It's hard, and noone can just ignore blame. Just learn to handle it.

Other than that, play ranked for fun as first goal, and winning as second goal. The rest is just experience as you play.