I originally started playing support last season because I wanted a challenge. I climbed back up to Gold playing Soraka, Leona, and Janna. I think the way a lot of people play support is what keeps them from picking up the role.
There's the player that thinks they're just a ward bot and thinks that standing behind their teammate and protecting them is always going to be enough. For sure, in some games you're going to do just fine, but in a lot of close games or ones where you're behind, you're going to lose easily. You need to carve out room in your lane and position yourself correctly every time. Always think about the next trade and how you can stay one step ahead of the enemy. Never let yourself get bullied because this season is really unkind to players who get bullied out of lane. You're already starved for XP and gold.
The next type of player is one who sees a lot of supports play like the one I've just mentioned, and they go the complete opposite route. They are way too aggressive and play like they're in a solo lane. They usually do this playing a mage, but not always. Sometimes they end up totally dominating their lane, but other times they contribute heavily to creating a snowball bot lane that consumes the entire enemy team. There is no stability. The matchup is more about if the enemy lane has an experienced support or not.
Playing support is all about knowing when to engage and when to play safely. If you've mastered that as a solo laner, then you're going to learn how to be a great support quickly. Another important aspect to enjoying support is figuring out who you like to play as, and where they excel at and what their weaknesses are.
Some people say you should play all kinds of different supports so you can fill out what your team needs. I disagree with this for two reasons. The first is that support is never going to be enough to fill out what the team is missing. You're always behind the rest of the team in gold and XP. The second reason is you should always play what you're best at in a competitive mode. Support champions do take skill, and you want to give yourself every advantage.
The last tip to enjoying the support role is picking the champion you enjoy, and it actually may not be an AP building support. There's nothing wrong with playing a mage bot if you do it correctly, but give others a chance. You want to enjoy the champion you're playing more than anything else.
I'm a Soraka main mostly, although I have been playing Lulu a bunch lately. I played a lot of healers in my MMORPG days, but I was pretty surprised I'd like playing one in a MOBA. A big reason I like her is that I get a lot of attention from the enemy team. I'm the number one target, and I can position myself and prepare better than my ADC can most of the time. I'm really good at baiting enemies as Soraka. I also am able to carve out room for my ADC in lane pretty easily as her now. So always remember you never know who you might enjoy playing.
In my opinion if you treat yourself with respect and realize you have the ability to contribute heavily towards a win, then you're going do great most of the time and most people will treat you with respect outside of Bronze and low Silver.
As for champion grades, wards are weighed heavily in support grading like any other role. That's both wards and control wards you place, and ones you destroy. Vision denial is very important. Oracle is pretty underrated as it is, but as a side note that trinket gives you so much added utility and you can do more with it than just deny vision.
Not to mention there are just a lot of great frustrating Janna players out there that can stop any fight they want. Some champions are difficult to get an S+ on due to their popularity, just like any other role. Getting mastery 7 on Janna was a bit difficult for me too, but I was also learning her at the time. So just be patient.