'ere we go
Mars: are you getting too much glare and therefore cnt see any detail? if so you might consider an aperture mask. also are you waiting for it to me high in the sky? if its too low it will just be washed out in the earth atmosphere.
nebulas: dont expect what you see in pictures. you will see in the bright ones green and that about it. alot of them will look grey. also use your lowest magnification to find them and view them. high magnification will wash them out. keep trying. if you have a 20mm eyepiece of higher use that.
hope this helps