Singed was, and still is my main champion I have played ever since I started. As soon as I saw Dyrus's pro champ pick and he picked Singed. I watched that video and thought, "I want to be like that." So I sat down, played singed, and instantly fell in love with him. He even fits my personality: crazy, funny, not very popular, and just being an annoyance in the battlefield

Pros:
Super fast
Farming is awesome
An annoyance in lane
Great team fights
Great tanking ability
Cons:
Small cc
Have to get close to enemy to poison them
High risk diving
mana hungry early game

Magic pen marks
Armor seals
Magic resist glyphs
Magic pen quints (or movement speed quints, your choice)

Go 9/21/0 taking only 9 magic damage Masteries, and all resistance, health, and tenacity Masteries

Last hit until level 2. Then run around, but still try to last hit until you have your rod, and seraphs.

Even though you do not have good initiation, that doesn't mean you can't jump into a fight. before you run in head first to piss off the enemies, make sure your ultimate is on, and your team is with you. Them start to run by yourself,(ghost is also good here!) around he edges of their team. They will all get greedy and try to chase you, while they do, they will waste mana, time, health, and their position. Once they realized that you're a lost cause, they will get surprised by your team. If you want, you can even head back into the fight to deal even more damage

Run around, flipping people.

Take your flip first. The only reason being is because it's your strongest cc you have. If you get invaded on your jungle, flip an enemy into your team, or under a turret in lane. If you take poison, you're gonna run out of mana very quick. Until you get items, you can only use your poison for farming or annoying your enemy laner.

Singed is like Ryze in a way. His passive grants him 2.5 health for every 10 mana you have. This is why I but archangels staff, and manamune. The bonus mana, mana regen, and health is a perfect combo on singed. Rod of ages also works very well. For mostly damage, take a Lissandry's Torement do deal even more damage over time. A rylai's is also great on singed for slowing enemy champions chasing you, slow them down so teammates can catch up, or even to make sure they enjoy that poison even longer. Some people take a thornmail on singed, and I can understand. But I personally like Frozen Heart, because it slows attack speed, movement speed, and gives you more mana, which means more health. You will be unkillable!

I sure hope is guide helps you with singed. It sure helped me. This is also a little bit of a shoutout to Dyrus, my favorite League pro. We have similar stories when I was growing up. I was bullied, ridiculed, exiled, so I know how you feel. If I would get one comment from Dyrus, I would feel like the biggest guy in the world.