Barbara has given GREAT advice here... if the ink on the paper is getting shiny and gummy... then there is too much ink on the paper in that one spot. It doesn't mean the paper is bad and it doesn't mean you are doing anything wrong... it just means the paper is fully saturated and can't take up any more ink. The denser the paper, the faster this will happen... (but the less you need to worry about feathering - pros and cons to ALL papers).
I like to use 6-10 shades and layers of ink... so I use a LOT of layers when coloring. I have learned to use a very little bit of ink for each layer to avoid this shine. But... it still can happen. So I know that when the paper starts looking "wet" then I need to stop and let it dry just a few seconds (30 or so) before adding more. This gives the paper time to soak up more ink instead of letting it sit on top. Now eventually, it won't be able to soak up any more and the ink will just sit on top and turn shiny and gummy. It's hard to fix after that point. (You can try to pull some of the gummyness off with the colorless blender marker, but this often just ends up messing it up and spreading it around.)
Barbara also mentioned using the side of the brush periodically. YES! If you find yourself using the tip a lot, then you might end up with the ink thickening up (from the dark pigments) inside the brush nib and then seeming gummy when it comes out. To solve this, do just like she said and carefully remove the nib, let it sit in a bag or container of blender solution or rubbing alcohol until it turns white or becomes mostly clean and then reinsert. Remember to periodically use the sides (all sides) of the brush tip to keep this from happening.
This site is a wonderful place to find info and the links that Barbara provided are good places too. Don't be afraid of asking questions... we are all here to help each other.