Until you understand proper Warding... and take this from some one who jumped into Ranked WAY to early (16 Champions and no Runes)... don't play Ranked.
Also Jungle is about the most difficult thing one can do when new to Ranked, because there is so much you have to focus on to be effective. Clear, Counter Jungle, Gank, Counter Gank, Neutral Objectives, Group vs. Farm, Map Awareness, Warding, Clearing Wards... I mean it's no wonder in your first match you had a bad experience. You took what for beginners is likely the toughest job of all and dove in.
Secondly, you have to REALLY know Comps to know how to Build. You may be right that Tri-Force is a good item on Vi... but if your team is getting smashed and needs a Tank, you got to be Tank Vi or you can't help them.
Feeders will happen. You simply have to get better to carry them 50% of the time. That's it, just salvage half the Feeder Games and you'll be ahead of the curve. More easy to say than to do, doesn't sound like much but it's a hell of a task.
Jungle and Top have a lot of similarities and Flex Champions... I suggest you work on Top until you get more comfortable with the pace of Ranked. Work with Teleport, and learn the right times to flip the map to help so you can Split Push without the constant "Never with Team!" crap. It's amazing what coming in for a few fights will buy you in 'Free Split Push' later in the game, because they know you ARE watching them, ready to join if TP is up and help if they need you.
Don't give up... but at the same time maybe cool off, adjust to Top before diving back to Ranked Jungle (less things to manage while you test the waters) and watch some Videos.
Now... when you died, HOW were you dying? Out played? They had better Mechanics? You didn't understand the Champion that killed you? You tried to help a Weak Team Mate (feeding) into a Strong Enemy (Fed Vel Koz)? Team Fight?
It's important to know these things to understand how to die less, so you can start learning how to Kill and Assist more, so you can Rotate to Objectives after Kills and Assists more. Because in the end, it's the Objectives that will Win the Game (Watch CLG beat TSM with NO CLG in TSM Base... Winions in the Pros man, playing the Map works).