Problems I have with Writing

Switching Between Past Tense and Present Tense

I don't know if anyone else does this but I know I do. I'll be writing in present tense but sometimes I slip up and start writing in past tense. Like this:

I sigh as the water runs down my back. It feels good to get off all of last nights dirt and grime. After a couple of minutes I shut the water off and get out. I slipped on a robe and head to my room.

See, there at slipped. I find that to happen a lot when I'm checking over what I write before I post.

Description

Sometimes I write too much detail and the scene become really long and dragged out. Other times it's the opposite, and when I don't have enough detail I realize it can leave the reader confused. Like I'll leave a part out and I know why the character is doing something and I forget that the reader isn't in my head so they are probably confused. I'm still trying to find my middle ground with this one.

There are probably other things that I have problems with but I can't think of them at the moment. My question to you is, what problems do you have with writing? Other than that, have a nice day!