I am a novice singer. Is there a simple way to strengthen and tune my voice?

Question:

I am a novice singer. Is there a simple way to strengthen and tune my voice?

I would like to learn to properly warm-up my voice and improve my pitch. The greatest difficulty I have is hitting notes. I can't seem to find the right note without sliding to it. I know I have a lot to learn, but I have to sing in an ensemble in a little less than a month and I think my lack of confidence is possibly the greatest hurdle I will have to overcome. Please Help

Best Answer - Chosen by Asker: do scales like do,re,mi,fa,.........each note hold for a minimum of 15 seconds. slowly get louder. and no squeeking or anything during through out.