Let's be brutally honest: Calculus concepts aren't what fail students. It's the algebra. You can understand the Fundamental Theorem of Calculus perfectly, but if you can't simplify a complex rational expression or recall your unit circle values instantly, you will fail MATH 151. I've seen it happen to hundreds of smart engineering majors.
Master The Algebra First
Before you even think about derivatives, go back and drill your algebra. Specifically, focus on exponent rules and factoring. In MATH 151 and 152, 90% of the points lost on exams come from 'silly' algebraic mistakes in the middle of a 2-page problem. If you can't factor a cubic polynomial in your sleep, finding limits will be a nightmare. Use purplemath.com to brush up—it's better than your textbook.
Don't Memorize Limits, visualize Them
The formal epsilon-delta definition (Lim x→c f(x) = L) is the first wall students hit. Don't just memorize the Greek letters. Draw it. Visualizing the 'neighborhood' around a point is critical for understanding continuity. If you're relying entirely on L'Hôpital's Rule without understanding *why* it works, you'll get crushed on the conceptual multiple-choice questions common in final exams.
The Integration Trap
In Calculus II (MATH 152), integration techniques like trigonometric substitution are the main 'weeder' topics. The trick? Don't start by trying to integrate. Start by trying to simplify the integrand algebraically. Often, a quick trig identity swap turns a 20-minute nightmare into a 3-line problem. And please, for the love of Newton, don't forget the +C.
Look, even with these tips, calculus is a grind. It's designed to weed people out of engineering programs. But treating it like an algebra test with some new rules on top gives you a fighting chance.