League of Legends (LoL) Question: Which Champion To Use?

"I can play really well against BOTS but I really suck when I play with my friends." The problem could be that you play too much against bots. Bots are only good if you're just starting to play the game or if you're testing some combos/getting used to abilities' ranges. The only solution to this is playing more normal games. You'll eventually get matched with people of your own skill level, or get better yourself and start doing things right.

Other than that, your friends and you might have a big skill gap. If their MMR is that much higher than yours, you'll get matched with people of higher skill level, and get stomped A LOT. If you don't mind the stompings and are willing to learn something from the enemy this is a quick way to get better, seeing what works for them and trying it the next game.

That said, a bunch of tips regarding mobafire:
-When you say your summoner name, remember to add your server too. There are 10 different servers and you could come from any of them. I guess most people here come from NA/EU, but even then, it's a drag to check it, not to mention if there is someone else with the same name in other server (I didn't find you in any server btw).
-The Q&A section is good if you want a correct answer to a question. Your "question" is more suited as a post. I don't think questions can be transformed to posts by admins, so I guess you could make a post and copy-paste the title/content in a new thread in the new player help section (http://www.mobafire.com/league-of-legends/forum/new-player-help).

Play nothing but Riven until you are a God at her, or at least so good that you consistently dumpster the enemy top laner. Don't literally play nothing but Riven, but play her when you can. Like if you are going jungle, you can play Riven. If you are going mid you can play Riven. Riven's best lane is top so play that as much as you possibly can. You will improve. You might lack the mechanical skill or proper game knowledge to play and do well with your friends right now, but after really focusing in on one champion, especially the challenging ones, and getting really really good at that champion the game will becomes 1,000,000,000 times easier to play.

Don't listen to the people who say to try an easier champion. Play what you want; that's the only way you are going to get good at them. The best way, especially for someone who is relatively new to league, to learn a new role or champion and be really good at them is to look up some videos on YouTube about the champion, some MobaFire guides, and go into custom lobbies (self-created lobby) and practice her combos and animation canceling techniques. Practice them until you think you've got them down, take those skills and test them in a real game so you can play against someone who is able to outplay/get outplayed by you.

Playing her in blind pick helps you learn things the hardest and most effective way possible by forcing you to experience what it's like to play in a favorable and unfavorable match-up as Riven. Just playing her will make you understand where all of her damage comes from, how strong she is at a certain point in the game and whatnot, allowing you to build her in ways that are adaptive to the meta/situation.

Riven was the first champion I took a liking to and I was told the same thing that you were when I played her. I have a friend who, at the time, was much better than the rest of the group and would always look at my lane to try and give me advice. I played nothing but Riven until every game was the easiest thing I've ever done in my life and then came into games like a god.

It honestly really doesn't matter which champion you play to this extent since the outcome will always be the same. Effort is very heavily rewarded. Climb on!

rivin is a champion with a really hith sckill cap so i seggesst that you start playing with a lower sckill champion like jax shivana or mundo tanks are eayer to play but there are still some damge champs

Test olaf :)

Riven is a high skill capped champion that involves a lot of practice and a lot of game mechanics/ knowledge. I recommend playing lower skill capped champions that have easier skills and game mechanics and then moving up to more skilled champs such as riven when you have mastered the basics. If you enjoy playing top lane playing reneketon may be an easier champion to learn basic mechanics. His kit has a lot of sustain and mobility similar to riven so you should have a smooth transitions. Hope this helped :P