Not sure if your calc 2 curriculum is identical to mine, but truly the best advice is showing up to your professors office hours and asking them questions about the fundamentals, I did calc 2 a long time ago so I don't remember the material but because I spent my time learning the fundamentals and the intuition of questions (rather than just learning a procedure) such that even if a question was asked that I have never seen before I would be able to recognize it and begin a solution for it and eventually find the part where it merges into "stuff I have previously learned" and go from there.
I'll go through what I remember of calc 2:
It started off with integration techniques, and review of basic integrals and the fundamental theorem of calculus, we first started with techniques like u-sub and integration by parts [for this, I REALLY recommend the D-I method you can find on blackpenredpen's channel, it was a life saver when I was doing fourier series integrals in diffeq1]. The elementary integration techniques with some other limiting cases that talked about even and odd functions (this is crucial for higher level mathematics, saves you a lot of the time). After we learned some basic integration techniques and practiced them- extensively. We learned trigonometric substitutions for solving integrals- I have genuinely never used this after the first midterm, it was more annoying than time saving or efficient. Generally there might be a second introduction (or maybe a first if your Calc1 class didnt offer it) for imaginary cosine and sin functions (cosh and sinh, remember their definitions and their respective integrals), generally: I didnt find these useful at all and even in higher level math classes I wouldnt make the substitution because it was either ugly or annoying to do. After that, you learn some basic shell techniques and closed volume techniques- these are pretty good, relatively easy, just rotate it about a certain axis and if you struggle with it imagine a 2D cross section being rotated around a specific axis to form a 3D shape, and you are finding the volume inside said 3D shape. After that we learned decomposition of fractions, and their uses in integration calculations, again if you have a strong math background capable of calculating these fractions without writing them down- you will breeze through this. We then learnt improper integrals, an extension of normal integrals that has a funky limit definition, its useful for checking convergence. Next you learn comparison theorem, truly I dont remember what this is, I never use it, looking back at my notes it looks to be something that can be derived by intuition. The fun part starts here: you start with normal series, learning about infinite and finite sums, then you learn about geometric series and how to find the ratio and finding the total sum of these large geometric series, I wont cover everything that the series unit teaches you, but you learn alot about general ways to solve a series question and most of your process will be to check if its convergent or divergent using a certain test- if a test gives you a numerical value that isnt 0 or infinity, it most likely converges, if its those two- depending on the case, its probably divergent. Then you learn about some polar coordinates stuff, and integration in polar coordinates for functions that are disgusting, like a cardioid function (I still havent ever needed to use this after finishing the class, but it was worth 20% of my final exam mark). There might be some spherical things in there, but those are generally not touched upon too much. Then you learn 3D coordinates and vectors, generally, these dont get too complex, I think the most complex theory you might end up learning is arclength parametrization and general function parametrization for calculating line integrals (CRUCIAL for calc3). As for each part, lets say there are 3 parts to Calc2:
1) Integration in cartesian coordinates, polar coordinates and spherical coordinates and their respective integration techniques: for these, its going to be a lot of practice to recognize what type of question you are facing and the technique to solve it. For 3D revolution questions, try to find some youtube videos showing a demonstration of the integration happening and why there are certain steps occurring throughout the integration. For polar and spherical just remember your order of your integrals, because especially in calc3- it gets extremely tedious.
2) Series and their respective forms of solution: for this one, make a general flow chart for each type of series and their respective solution, almost like a greenlight redlight flowchart telling you what the right solution would be, and try to memorize that, do not try to put intuition into series, there is very little intuition to be found there, focus on putting your intuition and full understanding into the next part.
3) Linear Algebra and Parametrization: start from basics, if you dont understand what your professor is saying, go to office hours, watch youtube videos (I prefer Dr. Trefor Bazett on youtube, he takes it step by step and has nice animations accompanying the math), once you understand the BASICS, move on to understanding what the professor is explaining and try to piece together WHY youre learning this material, as it helps you gain a deeper understanding, for this unit and unit 1 you really need to practice questions, there is no way around it, you need to practice your understanding but this unit challenges your critical thinking skills far more than the integration unit, as they can throw a place at you and a line along the plane and ask you to do just about anything. Don't bother practicing questions until you fully understand the theory, if you dont understand the theory you will not be successful in this unit.
TLDR: Train your brain to recognize certain integrals and their respective 'approach'. Memorize a flow chart of all the possible solutions for series questions. Learn the theory and ONLY then start the practice questions for linear algebra & parametrization integration.
EDIT: Textbooks are good sources for knowledge, but try not to do too many practice questions there- as the questions arent representative of what your professor will be asking, unless you specifically know your prof asks homework questions from the textbook (profs that ask hw questions from textbooks typically ask exam questions that are just modified textbook questions), if you need some textbooks on the subject, I can send you some, or if your school uses a strangely specific one that costs more than $20, send me the ISBN and I can send you the digital textbook.
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