Answer :
Find a common denominator to begin. The common denominator is the LCM of both denominators. In this case, the common denominator will be 24.
Now, multiply the numerator by the number you multiplied the denominator. For 2/3, you multiplied 3 by 8, so multiply 2 by 8 to get 16. The fraction is now 16/24. Multiply 4 by 3 since you multiplied 8 by 3 to get 24. You will get 12 and the fraction will become 12/24.
Then, compare. 16/24 is closer to 24/24, or one whole, so 16/24, or 2/3, is greater.
Ok a strategy I use is I make the fractions into decimals like money and then I compare which one is bigger. So 2/3 as a decimal is 1.5 and 4/8 as a decimal is 2. So 4/8 is greater than 2/3. The way I got my answer was that I divided 3 into 2 and got 0.5 and I divided 8 into 4 and that 2. I hoped I helped.