Ok.Let me be completely honest.You are by default getting matched with people with your current Mmr or a bit lower/higher.Lets say its 1000.So you,your opponents and your teammates are on roughly the same skill level.This means that the only constant in your games are you.By default you are gonna lose 30% and win 30% of your games unless you are literally trolling/braindead.This means that 40% is up to you.Lets take me as an example.Last season was my first season of playing league,and by the end of it i was lvl 30 and got placed in s5 where i played like 3 games.Stayed there.Then this season,i went 7-3 in my placementd and got placed into B5(!).Tbh people in b5 are literally bots.I stomped my way trough bronze and silver all the way up to gold 4 where i currently am.So i was in the same place as you were,yet somehow i escaped the so called Elo hell.Now you know some people say just pick yas/riven/vayne etc,and hard carry.Now im not sure how to break it down for you but,you,at your current skill level wont be using 10% of these champs capabilities.Actually imo only plat plus people have any idea how these champs work and can utilise them properly.So dont bother with being flashy.Pick something simple that is both viable right now and you like it.I am saying this because you will not have to worry about combos,mechanics and other bs and you will be able to focus on your decision making.Trust me there are tons of people i diamond who are on a mechanical/outplay/you get the point level of a motherfucking spoon and they themselves admit it.They got to high elo by outthinking thir opponents and not by outplaying them.Also you will ALWAYS climb,as long as you are just a bit better than your opponents.It may be a slow process,but it will happen.So if you arent climing at all you deserve to be where you are and thats a fact.Now just learn from your mistakes.For example you are the supp(lets say lulu) that just got ganked by an Evelynn because you were pushinh their bot into their turret.Now their Draven got a double kill and the lane is pretty much over.Lets say Eve came trough the trybusb or river(doesnt matter) Why didnt you have a pink,why didnt you ward her red or golems.Did you look at thr minimap to ser ig shes been spotted somewhere.Why didnt you w her when she attacked?Did you slow them down?Did you peel enough?Did you tell your ADC not to push since you have no idea where eve is?Think about every situation this way.Always literally try to blame yourself because you couldve done something more,or couldve not done something.Basically,what im saying is play to improve and not to win now.Because if you get lucky and get good teammates,nexg game theres a chance you get a braindead top laner and a leblanc that goes bloodthirster into deadmans plate.So play to improve,and as you improve,so will your rank.Also,huge thing,always buy a pink.I dont care if you think its a waste to spend 750 gold a game on pinks.But for example,750 gold is 10 pink wards.Imagine dying 10 times or yout teammates dying 10 times because you didnt have those wards.Thats 5000 money and a few turrets,maybe even drag/baron going to your opponent?Was it worth to spend 750 gold over a course of a,lets say,35 minute game to prevent that from happening.Also,always be nice to your teammates.Be that guy you would love to have in your games.Spread them positive vibes around.Its gonna help trust me.Also,dont build shit from mobafire or probuilds.Because build options are ALWAYS SITUATIONAL.For example they got Liss top,LB mid,Fiddle jungle,Nami supp and an adc.You are garen top.I know that sunfire/deadmans is core on garen and that all the pros build it.But for the love of god dont rush a sunfire cape into a lissandra.Also,when not supporting aim for 10-15 wards a game.When supporting try to have around 30.Also dont ward just because you know you should,and dont ward the same spots every time.Ward the paths that the opponents take.Lets take this as an example.You are the mid laner with no escapes,lets say viktor.The enemies have zac jungle.Ward his Raptors,and the bush parralel to his blue,alongside warding sidebushes.Also notice his pathing.That way he cant gank.And just like that you dont have to worry about being camped.One last tip,adapt to their teamcomp with your own pick,and play around important cooldowns(shen ult,amumu ult,summoner spells etc).Also answering their teamcomp with a playstyle is important.Dont group up alot against mf/amumu/sejuani/kennen/yas/malph etc.Opt for a splitpusher instead.
Hope i helped,sorry for the wall of text,i dont have other stuff to do atm so i thought i might as well be helpfull.