Count the decimal places then write 1 in front of the same number of zeroes. Example: 0.1234. 4 decimal places so write 10000. Now take away the decimal point and make a fraction: 1234/10000. The fraction reduces: 617/5000.
For recurring decimals count the decimal places over which the recurrence occurs and divide by the number made of as many 9's. Example: 0.027027027... The recurring pattern is 027, 3 decimals. 027/999=1/37.
For decimals with a recurring section, force the decimal point so that it is immediately in front of the recurring part by counting how many decimal places there are before the recurring pattern. Example: 0.0583333... 3 decimal places before the recurring 3. Now multiply by 1000 (3 zeroes following 1): 58.333... Remember we multiplied by 1000. The recurring part is just one decimal, so we make the fraction 3/9=1/3. The large number is therefore 58 1/3. Convert this to an improper fraction: (3*58+1)/3=175/3. Now divide by the 1000 we multiplied with earlier: 175/3000=7/120.