increase humidity

What kind of humidifier do you have? That is a small grow space and shouldn't be a problem to raise the humidity. Without knowing more I would say put your ventilation on a timer so your not venting the humidity constantly. A humidifier with humidistat control is a must.

Without more specific information, your question is difficult to answer. For example, the running time of your ventilation. If this runs all the time, you will never have more moisture inside the tent than outside. Added to this is the temperature inside and outside. As the air warms, humidity falls (hence relative humidity). And what is your goal and how much do you have outside of it?

I use a very high tech system... I take a towel, I soak it in water and wring it out just a bit and then hang it in the tent. If the humidity doesn't come up to where I want/need it to be, I add another towel. Works like a charm. 😎

Higher humidity is better in some sito's, but if you cant get there its fine. I grow outside and its an average of 30% humidity during my grow. Unless it rains. lols. The plants will just transpire a bit more if its not as humid as u would like, so make your nutes a bit weaker to allow for this- this may mean feeding a bit less/using weaker nutes but feeding a bit more often, or feeding as normal but just using weaker nutes as u will have to water more often. Thats about it, humidity is only a real issue when its too high. You can adjust if its too low ok. Dont stress, id rather lower humidity anyways to better avoid the dreaded bud rot. But if your set on getting the humidity higher then you need a bigger humidifier plain and simple- the one u have is too small for the space, or your not filling it up often enough and its running dry. Anything else is a stop gap temporary solution. Bowls of water and wet towels are not signs you have a good set up and are hazards in the grow environment. As said below as long as your plants are in a relatively normal outdoor like humidity range of 30-60% they will do fine.

Can also hang a damp towel to increase humidity in tent. Just have to re wet it regularly

Well turn your humidifier up if you have it at a minimum. As long as you are over 30 percent, less then 65 percent you are within growing safe Conditions.