I find that the PEMDAS is the easiest way with the saying Please, Excuse My Dear Aunt Sally. Make sure your student commits this to memory. It is vital to his or her progress through math. Also make sure they understand what each step implies by the use of the 1st letters. I have had many students that could tell me the saying, but could not tell me what it meant they should do.
Also very important - multiplication and division should be completed in the order which they exist in the propblem from left to right. ( addition and subtraction is the same way)
Example : 15 ÷ 3 * 4 = 5 * 4 = 20 NOT 15 ÷ 12 = 1.25
----> many students want to do the "M" first because it comes before "D" in the saying
Example: 12 - 5 + 3 = 7 + 3 = 10 NOT 12 - 8 = 4
Keeping in mind that everything within parenthesis should be reduced to its simplest form before going to the next step. Since this is 6th grade, everything in parenthesis will probably reduce down to 1 number. Then you can do the exponents before proceeding to mult. & div. etc.
I always try to give an analogy that may stick with a student. Think of the order of operations like socks and shoes. IF you are going to wear socks, then you put them on before your shoes. Likewise, parenthesis before exponents, etc. However, you may not always wear socks. So you just put on your sandals. Every problem is not going to require that you do every step of the order of operations. If there are no parenthesis, then go on to exponents, or mult., which everstep comes 1st, and proceed from there.
If you still need some help just repost and I will try to locate some practice or powerpoints that I am sure I have (somewhere).