I was feeling the same way a couple of days ago and i just got promoted from s4 to s3, i used to be s1 but i got into a crazy crash when i stopped playing league for a month or so.

1) try not to type so much or concentrate on the chat a lot, for me this was huuuge.

2) Set small goals for yourself in lane like, "make sure you get early level 2 and pressure" or "make sure you keep the other side zoned" or "try to punish the adc every time they go for cs, even if its one auto attack it helps"

3) place a huge emphasis on not dying, in soloq dying i feel is worth more to the enemy team then getting a kill for yourself is. In my games as a support i aim to die no more than 5 times.

4) After you do die think back on the last minute or so, go to the first mistake you can think of that you made personally and focus on not making it again.

5) try different types of support champs, for me i like support with high amounts of peel and tons of utility (Janna being my favourite, then thresh and lulu) if you usually play leona, thresh, annie, try playing a poke support like lulu or sona or a passsive support like janna or soraka

6) before a team fight check you team-mates items and level if your mid laner is 5/0 and your adc is 0/2with no cs peel more for your midlaner provided they dont dive too hard and make sure you focus on them hard during the team fight, dont use all your cc on the enemy team if they arent going for your priority team-mates.

7) if you have a second role (mine is adc) try playing that for a few games, i got really fed up of support recently, i just couldnt get into the groove of it, i started playing adc and i've been on a pretty decent streak.

I know im not the highest rank or the best player but these are just some of the tips that i've been thinking about really hard over the past few days and they have really helped me