Lukaku, 24, has been at the centre of a spat between United fans and Red Devils manager Jose Mourinho, with the latter unhappy with the perceived lack of support from the Old Trafford faithful for the Belgium forward.
After a blistering start to his career at United, Lukaku has gone without a goal for the club since netting in a 4-0 win over Crystal Palace in September.
"I think a lot of people are judging me as the finished article," Lukaku said.
"I'm 24 – you can't judge me as the finished article. I'd rather have a year where I improve, improve, improve rather than going straight to the top and then declining.
"I know I have a lot of talent. I can do a lot of stuff, score goals with my left, right and head. But I want to be a creator – I want to have more assists. I want to make sure when my team is having difficulties they can count on me.
"I'm on the perfect stage and the perfect age. I want to be a winner and take my career to the next level."
Lukaku has scored 11 goals in 16 appearances for United since his £75m ($98m) move from Everton in July.
Mourinho said he was "disappointed" with the lack of support for Lukaku in the club's 1-0 win over Tottenham at Old Trafford last weekend.
"I would like the supporters to explain to me why they don't support him so much because he gives everything and I think it is not fair when scoring the goal or not scoring the goal [he] makes the whole difference," he was quoted as saying by the Sunday Telegraph.
"I don't think it is fair at all. So, I'm a bit disappointed – but not with him. With him [I am] very pleased."