Basically what the title says, im interested in learning this game and it seems that a lot of the strategy and speed comes down to getting as many perfects as possible. Unfortunately i am having trouble getting the hang of how to get perfects when you aren't upgraded at all. Any advice on how i can get better at this?

Honestly it just about feeling, i got consistent perfects on 1st deck after about 120-130 decks, so just muscle memory i guess

What Quaver said, I also think when starting out it helps to take the first swing slow and let the hammer/wrist set itself before swinging.

The best advice I can give is to hit the nail with enough force, so start high up and move down fast but accurate. Eventually you get that "feel" and "rhythm" to be consistent enough with perfects

I will try to give my 2 cents to it: A big part for me is to have a consistent setup (how am I holding my mouse, how am I sitting, how am I moving my hand) to be able to create muscle memory, which gives the best results for me. Then there is figuring out how much force you need for a perfect hit, which varies when you buy the Hammer Upgrades. The amount of force required sinks significantly, at max Hammer you need about as much Force as when tapping a Glass Nail in the beginning, maybe a little more. You are right, the most important thing for speed is to get perfect Nails and as many of them in a row as possible, because the Multiplicator is the biggest factor, which you buff with the Plank Upgrade. The Nail upgrade seems to play into the Multiplicator aswell, but I am not sure by how much, still working at that.

Outside of holding your combo, you can get quite a bunch of money just through the Hammer upgrades, at max Hammer Rank you get about 3k$ per perfect hit, it quickly adds up. The Hand Upgrade is not as important in my opinion. Upgrading it results in you being able to hit the Nail a little deeper, potentially reducing the amount of total hits required. You notice this the most with no Hand upgrades, you need quite a lot of okay hits, upgrading reduces that. Only at the max Hand Upgrade you are able to get a Perfect Nail in 2 Hits, anything outside of that I feel makes it harder to achieve 3 perfect Hits, since then the Nail is way lower and it gets easier to hit the Hand or the Plank, killing your Combo.

I wouldn't bother with the Bug or Passive Money upgrades, for example Deck 1: with all perfect hits, full combo, you can get bit more than 4k$, while one bug gives you 10$, which is peanuts in that case. But if you struggle with getting more than 200$, and hitting 3 bugs, suddenly you could get enough money for 1 nail, 1 plank or hammer, which makes it easier for you to jumpstart your run.