Thumbnails: Your thumbnails are great they are very eye catching and if I were scrolling through searching for a video like your euro truck series I'd definitely want to check it out.
Channel Art: Your channel art is good but could be better, you want your channel art to kind of represent what your channel is about, for example a Banner like MarsBarsGaming's would represent that his videos are very out going and joyful when he is playing his games.
Videos: I watched one episode of your euro truck series and did not want to watch anymore, you were never talking in it. No one will want to stick around and watch your videos if you are just going to sit there and not try to be entertaining, its kind of like going up to a girl you've never talked to in your life and asking her out, she def going to be like "WTF Who the heck are you?!" and then probably be creeped out by you forever.
Your video quality is good though you have 720p videos and in todays youtube community HD quality is a HUGE must.
Mic: I do think your mic needs to be upgraded to a better quality mic, Its not necessary because you are just stating off but I'd try to make your audio a little better, idk what you could fix but your mic just didn't sound good in your introduction video. But again its fine for now, I started with my audio sounding the exact same, but i just upgraded my mic after a while.
Here are some microphones you might want to look into buying in the future:
Audio Technica AT 2020
Audio Technica ATR 2500
Blue Snowball
Blue Yeti