HI,I am trying to get various achievements for being neutral, and i just cant do it, its too dificult i keep somehow being good or evil before i get to the required level. How do i do it

In a general sense, you want to do a roughly equal amount of good or bad things throughout the game.

In a specific sense for the achievements, you want to just save shortly before hitting levels 7, 14, 20 and 30 and do bad or good things to change your karma before you level-up.

If you're good, go on a bloody rampage in a city right before you level-up... stop killing when you hit neutral. If you're bad, donate to a church or do a positive karma quest before level-up... etc.