I was asked how to get fast on Sunday. It was an interesting question. If you are asking this question, then you probably want/need some guidance, if you don't want to go down this road of self inflicted pain by yourself.
There is the mindset some have, that others are more gifted or just made to be faster. Maybe others can experience pain in different ways or are made to fight through it better. I've seen some perfectly fit, 5% body fat type guys ride real slow, while some chunky 20% body fat guy go way faster. Some say, "oh he's fast because he was a runner in college." I'm no doctor, but I'm pretty sure you don't use the same muscles riding as you do running, or maybe some, but I am a believer that runners know the pain, they are ok with it, they may actually like it, and they push through it.
My best answer for how to get fast if you are new to racing is being consistent, setting short term goals, and understanding that you are going to suffer worse than you think you can.
Being consistent to me means riding your bike every day. Maybe you ride so hard that 1 day you don't ride at all, that is fine. But if you have a good base, and you are sort of fit, and ready to improve, I would ride as much as possible. 2 a days are best. If you like running, run. If you like riding on grass in the parks, do it. If you like climbing hills, ride up hills. You should ride a lot, mix it up so you don't get bored, and don't stop. Set your alarm 30 minutes early, get up and go jog for a mile or 2 before getting ready for work. When you get done with work, and your tired, don't feel like being fast, think about what I just said and go ride your bike super hard for 40 minutes, or an hour, or whatever time you do have before eating dinner.
When you are racing or riding practice races, keep your head up, watch what others are doing, what lines are they taking, what gear they are in and when they are shifting. Get to the race early, watch the masters race, check out each section of the course that looks tough, see what gears they are in, where they are on their bike when they are making the turns.
There's a lot more I can say about riding a lot, but you won't get fast without consistency, maybe 6 months of it.
For short term goals, these are very short term. Maybe your goal is to be at the start line on the first row, prepared and early. Or maybe the goal is to win the first lap, or get the hole shot. You set up these goals, and go harder after you reach them. If you kill yourself completely to be in the top 5 after two laps, you better not quit when you see 3 or 4 laps to go, you dig deeper to keep it.
Other short term goals can be to ride 10 hours in a week, or keep your hr above 180 for 5 minutes, something short that is attainable.
The last part about suffering, you either get it or you don't. No one going faster than you is suffering any less.