Hey there bud. That's a great way of starting out. Sources are the most important elements and evidence in any history discipline, and some could be rather intimidating but the method you described is really what you are looking out for when you ever have to assess and examine a historical source.
I'll expand on the method you provided, and ask the following questions when you are dealing with a source
ORIGIN - Where did the source come from? Is it a secondary or primary source? Where did you find it?
MOTIVE - Why was it written? Is the author or publisher displaying any hint of bias? (does he sway to one perspective or another?), and most importantly - what did he or she have to gain (or lose) from publishing the source?
AUDIENCE - Sources all have audiences. Who were they? Was the source an act of political or personal gratification or was it aimed at a specific sector of the community?
CONTEXT - Context is about time. WHEN was the source published? Rember that in the past times were different. When you read a source you are reading it from a modern perspective, or context. Eg: Our modern values of freedom and liberty (or anti violence - whatever you can think of) would stain our views of past societies such as Rome and Greece because of their context.
PERSPECTIVE - Similar to context. What was the author's (or reader's) perspective? What were their beliefs and etc...
Reliability - How RELIABLE is the source? Just because it is a source does not mean it is true. Look for clues on its reliabilty, for example - was the source written by a professional or amatuer? Was the author bias or tainted by a particular view? Was it a political advertisement or a factual recount? etc etc...
Its been a while since I've done HSC history (I'm studying history at University) so things might have changed but the main elements of assessing sources I have mentioned above (from what I remember). It just takes practice and commitment and you'll get there. Good luck.