Don't take this the wrong way but read the manual! But don't try to remember it all - just pick some basics, work on them then move on to the next step. Post images here for critique but remember everyone who replies will be slightly biased towards what they like to see in an image, and we're all different. So some critique you may feel is not valid for what you are trying to achieve, but some will be. Probably more important is to look at other people's images, pick from them what you like and ask yourself 'how was that done?' (or ask).