The Ten Commandments:
 Aseroth ha-Dvarim

Sh’mos 20:2-7

1. I am Hashem, your G-d, Who has
taken you out of the land of
Egypt, from the house of 
slavery...

2. You shall not recognize the 
gods of others in My presence.You 
shall not make for your-self a
carved image nor any likeness
of that which is in the heavens
above or on the earth below or
in the water beneath the earth...

3. You shall not take the Name 
of Hashem, your G-d, in vain, for
Hashem will not absolve anyone who take His Name in vain.

4. Remember the Sabbath day to sanctify it. Six days shall you 
work and accomplish all your work; but the seventh day is 
Sabbath to Hashem your G-d; you shall not do any work-- you, 
your son, your daughter, your slave, your maidservant, your
animal, your convert within your gates-- for in six days Hashem
made the heavens and the earth, the sea and all that is in them,
and He rested on the seventh day. Therefor Hashem blessed 
the Sabbath day and sanctified it...

5. Honor your father and your mother, so that your days will be
lengthened upon the land that Hashem, your G-d, gives you...

6. You shall not kill...

7. You shall not commit adultery...

8. You shall not steal...

9. You shall not bear false witness against your fellow...

10. You shall not covet your fellows house. You shall not covet
your fellows wife, his manservant, his maidservant, his ox, his 
donkey, nor anything that belongs to your fellow.

 If we consider that the Ten Words, or Ten Commandments 
are given in order of importance, which is easy enough to do,
then we can ascertain that the most important Commandments
would be those relative to how we directly affect/respect
Hashem.

  So we are commanded firstly that G-d "IS", and that we shall
have no doubts to His existence. That He exists is paramount
for anything in this universe, so in respect of this fact, it is 
stated first. The first third of the Ten Commandments deal directly
with how we respect the aspect of Hashem "being". 

 Next we are referred to the Sabbath. Again, if we are looking 
at the order of the Commandments, Shabbat observance falls
immediately after Hashem in respect to priority of attention.
Shabbat was made directly after man was placed upon the earth,
it’s sanctification pre-dates history. It is apparent then,
that this would rank high as it does in our list of priorities.

 The following six Commandments reflect on how we deal with
each other, man to man if you will. Only after we have realized
the  preceding four can we bear fruit from these. We can look at
the Ten Commandments as a ladder by which we can approach
Hashem. Without the first four rungs on the ladder, Hashem is
unattainable to us. No matter how well we respect each other
on this earth, without proper respect of Hashem, and of Shabbat, 
we cannot attain the highest point of the ladder, and Hashem.