First Water Change Advice

I'm extremely new to fish keeping and plan on doing my first water change tomorrow for my 20 gallon tank. I was hoping that somebody could help me out with it.

From the guides I've read, I've prepared to:
1) Unplug the heater and filter
2) Clean filter
2) Use siphon to suck up debris from under rocks, gravel, and water
3) 20-40% water change (I'm not too sure on this? Different guides suggested differently. My ammonia levels are still a bit above, so I would assume I'd need a larger water change)
I plan on using a water bucket to pour the water in after using water conditioner and making sure the water temperatures in the tank and bucket are somewhat similar
5) Replug heater and filter
6) Finished?

Is there any steps that I'm missing? I've read that this is also an opportunity to clean decorations, but I'm not sure if this must be done during every water change. Will taking out all the decorations every time like that stress the fish?

Any advice or tips would be appreciated too! I already messed up a bit with not cycling long enough due to lack of knowledge and I really don't want to make another mistake! Apologies if this question was already asked before, I just want to make sure my own understanding is correct!

 

Sounds mostly good. There are a few things to fix though:

-What are the numerical values of your ammonia, nitrite and nitrate in your tank?
-When cleaning the filter, make sure it is rinsed in water from the tank. Normal tap water will kill off the bacteria in your filter.
-No need to clean your filter so often; once a month is usually fine.

 

2) Clean filter

My levels are still a bit above

If you show ammonia I would lean to a larger size change but don't clean the filter. You will just loose any new beneficial bacteria you grew. Dont listen to the manufacturer, they just want to sell filter pads. Depending on the model, a rinse in tank water or a rare replacement would do.

Make sure the water temperatures match. Fill the tank with water that's the same temperature as your tank. Dechlorinate if applicable.

 

Sounds mostly good. There are a few things to fix though:

-What are the numerical values of your ammonia, nitrite and nitrate in your tank?
-When cleaning the filter, make sure it is rinsed in water from the tank. Normal tap water will kill off the bacteria in your filter.
-No need to clean your filter so often; once a month is usually fine.

Ammonia looks to be maybe a little over 1.0, and my nitrates seem to still be at 0. I haven't gotten the chance to test my nitrates yet.

And got it, I'll skip the filter cleaning this week then!

 

If you show ammonia I would lean to a larger size change but don't clean the filter. You will just loose any new beneficial bacteria you grew. Dont listen to the manufacturer, they just want to sell filter pads. Depending on the model, a rinse in tank water or a rare replacement would do.

Would 40% be too much?
And got it, I think I'll skip the filter cleaning this week then, thank you!

 

I don't think 40% is too much but I think there is some ideal amount of ammonia to leave to feed the cycling tank. If there are any stressed fish involved you don't really have a choice.

 

Yes, do not clean the filter. The rest is good.

My advice after the tank has cycled and others may disagree.
Test for Nitrate. If they are 10 or less, don't change anything. If they get to 20, then do a 25% change. A short time of doing tests should give you an idea how often it needs to be done.