While Titans is far from a perfect show and has its fair share of issues, particularly in it's writing, one thing it has managed to do well is have all the of the team be on different levels in of skill and power but still have each one feel like strong competent fighters.
The more grounded setting also sets it up in a way that makes sense for the more street-level heroes to operate on the same team with characters that are basically gods. It is also good at establishing their character's abilities and how they stack up against each other, even if it isn't the best as helping them grow those powers.
Robin
Jason Todd is trained by batman.
He is a more skilled fighter than both Gar and Rachel and was also able to subdue metahuman Arthur Light on more than one occasion. Despite this, he is still the weakest member of the team. He is going to need to seriously step his game up in order to be a real threat to the team as Red Hood in season 3.
Hawk
Hank Hall doesn't have any powers and only has training in the form of being the top player for his school's football team, The Hawks.
Due to his lack of formal training, Hank's fighting approach is a lot more reckless and aggressive than that of his fellow Titans. He was able to temporarily restrain Rose before becoming distracted.
Dove
Dawn Granger is the second person to hold the "Dove" mantle after Don Hall. Dawn is a trained gymnast, professional ballerina, and has seven years of training in jiu-jitsu.
She is on or around the same level are Dick Grayson and is able to take on street-level criminals with ease but struggles with enhanced characters like the Nuclear Family.
Nightwing
Dick Grayson was the first Robin and the original sidekick of Batman before venturing out on his own to become a police officer and eventually taking up the mantle of Nightwing in season 2.
While he doesn't have any superhuman abilities, he was trained by Bruce Wayne, one of the world's best fighters. He primarily uses hand-to-hand combat and various gadgets such as his pair of escrima sticks to fight his opponents. He has proven himself to be a capable leader of the titans and has even been able to hold his own against opponents like Deathstroke, Nuclear Mom, Nuclear Dad, and even the other enhanced of his team.
Beast Boy
Garfield "Gar" Logan was living in Congo as an orphan and contracted a disease before he was saved by Niles Caulder who then brought him to the US to live with him and the other of what would be known as the Doom Patrol. Logan's abilities allow him to shapeshift into animals.
So far, the only animal he has been able to turn into is a tiger, aside from the one instance when he managed to transform into a snake. The one caveat to his abilities seems to be that whatever animal he turns into has to be green. While he is a pretty skilled fighter as a human with him being able to take out several Cus agents, he mostly relies on his animal form during fights.
Ravager
Rose Wilson is the daughter of the villain Slade Wilson aka Deathstroke who was trained to be an assassin by her father. She inherited meta-human abilities from him, specifically her advanced healing factor which allows her to rapidly recover from severe injuries in a matter of seconds.
She is also a skilled swordswoman, often using her Katana in fights. She was able to defeat Hank Hall as well as keep up with and severely wound her father, killing him and rescuing her brother in the process.
Wonder Girl
Donna Troy is the foster daughter and former sidekick of Wonder Woman who was taken in after the death of her father at the hands of an arsonist. Donna's Amazonian physiology grants her superhuman strength, durability, and agility.
She was trained by the Amazonians in Themyscira and has a golden lasso that she often uses against more powerful opponents. While she was almost killed by Deathstroke, she was able to deal some blows to and withstand blows from Conner. She was able to able to defeat Kory in a fight, snapping her out of a homicidal trance. She ultimately died from electrocution while saving civilians from a transmission tower.
Starfire
Koriand'r is a warrior princess from the planet of Tamaran. Her alien genetics make her extremely strong and durable but her main power, which is to emit thermal blasts of the solar energy she absorbed back at others, comes from the sun.
She was able to overpower Deathstroke, Shimmer, and the Nuclear Family even proving that she was just as capable without having to use her thermal blast.
Superboy
Subject 13 aka Conner is a clone created by Cus Laboratories using the combined DNA of Superman and Lex Luthor. Due to his half-Kryptonian DNA, Conner shares the majority of the same powers as Superman including superstrength, superspeed, freeze breath, enhanced senses, and laser vision.
The only major power that's different between them is rather than the ability to fly, Connor instead is only able to leap extreme heights and over great distances. He was able to take on almost all the of the team with relative ease, including Donna and Kory.
Raven
Rachel Roth is the daughter of the demon Trigon. Unlike the other powered of the Titans, Rachel's powers aren't metahuman abilities but are supernatural in nature. She has demonstrated a wide array of powers including but not limited to telekinesis, telepathy, illusion casting, superhuman strength, and astral projection.
The range of her powers is still relatively unknown but she is easily the strongest member of the team but is also the least experienced which can often make her a liability to those around her. Currently, her most impressive feat was being able to overcome her father's influence and completely disintegrate him.