silver 2 trying to climb question

me and some friends have been trying to climb to gold 4 solo and sometimes duo and at the point we hit silver 2 the games seem to get so much harder and hit a losing streak landing some of us back to silver 4.im a support main and mostly play velkoz in majority of games and do well most of the time.ive had higher elo players look at my games and not have a clue why this is happening,i build for the situation,i ward properly and i roam quite a bit to help mid or jungle.im always looking at the map and i never flame in chat.i stop playing normally after losing 2 in a row yet after 300+ games i seem to be stuck.i have got to silver 1 promos once which failed and normally always silver 2 at 51% winrate and positive winrates with my main champs.my question is what would be the best way to break out of this elo?my friends tell me different advice as in i should otp velkoz while others tell me to never duo and that i need to play more.any advice would be appreciated.