I'm having trouble getting past 8-1 in super mario bros. Any strategies for me?

What time are you aiming for? Any sections specifically causing you trouble?

Just win

If you're new to running the game then I'd highly recommend not going for the pipe jumps. Since that's the hardest part of 8-1. Don't try to go all out like WR, just play cool. It's perfectly normal to go slow in any of the levels for a first PB. If you already have runs of it though then try to play it slightly faster in attempts over your PB.
That's my personal suggestion.

i want to try to get a time under 10 mins

keep in mind im using a emulator

From what I know Emulator isn't slower than a NTSC NES. I'd suggest watching runs around the time of your goal (for instance watch a run that has a time of around 9:00 since your goal is under 10:00), and see how they play 8-1.

Kosmic has some good tutorials on how to get a sub 5 speedrun. He goes through every strategy and gives ideas of how to sometimes "play it safe." I suggest watching this

If you are going for a speedrun try playing 4-1 to get used to pipe jumps so they can seem easier in 8-1

thanks for the video

If you just want sub-10 (or even sub-6 or sub-5:30 or sub-5:10 or even sub-5:05), then consider grabbing a fire flower so that you can kill all of the enemies in your way and not have to do pipe jumps.

That's a good idea, thanks.

since you said sub 10 you could try playing it safe and go down the pipe in the level
or do periwinkle's idea

Like periwinkle said, I would highly suggest doing your runs with a fire flower. It makes world 8 much easier and safer as you can take a hit and not die. 8-3 especially is made easier as you can just shoot the bros out of the way.

Here is an example way you can beat 8-1 safely as small mario

And then I guess if you have fire flower you can do this stuff

I could probably find ways to make it even easier if I spent more time