1. Focusing on Food

To focus to the extent that people begin to worry about eating more than actually fasting. This also goes along with spending heaps of money on iftars even though a person does not need to eat that much food.

2. Making Sahoor much before Fajr

Eating sahoor a few hours after Tarawih or Isha prayer is wrong. It should be taken closer to the time of Fajr.

3. Forgetting Intention of Fasting

There are people who don’t make niyyah (intention) for fast, as they think this is something which is in heart and doesn’t need to be verbal. They also think the intention needs to be made once at the beginning of Ramadan and not every single day, which is wrong.

4. First Day Fasting

If you find out late that Ramadan has started, you should stop eating and fast for that day, making that day up after Ramadan/Eid ends.

5. Tarawih Prayer

About Tarawih, some think that it is not prayed on the first night of Ramadan, believing it should be started after the first day of fasting. They forget that the Islamic calendar runs on the moon, Maghrib is the start of the new day.

6. Eating or Drinking by Mistake

Many people believe if you eat or drink by mistake this breaks your fast. This is false. If you happen to eat or drink by mistake then you continue fasting and do not need to make up for the day.

7. Using Miswak or Toothbrush

Many people think you cannot use a miswak or toothbrush during Ramadan. This is false, for the Prophet (peace be upon him) would use miswak during Ramadan. Also you can use toothpaste; the reasoning by the scholars is that the miswak has flavor, thus toothpaste is okay to use [if you are not eating it].

8. Intimacy

Many believe sleeping with spouse during the whole month of Ramadan is forbidden. This is false, you cannot do this only during the times when you are fasting. Between Maghrib and Fajr it is permissible to do.

9. After Menses

Many women believe that if their period has just ended and they did not make ghusl, they cannot fast that day (considering their period ended at night, and they went to bed without ghusl, waking up without having a chance to make it). This is incorrect, if a women has not made ghusl she can still fast.

10. After Intercourse

Many men believe that if he has had intercourse with his wife and did not make ghusl (similar to the above) then he cannot fast the next morning. This is also incorrect, for he can fast even if he has not made ghusl.

11. Prayer Times

Some people pray Dhur and Asr prayers together during Ramadan. This is incorrect and should be avoided.

12. When to Start Eating

Some people believe you cannot eat until the caller to prayer is done calling the Maghrib Adhan. This is incorrect, as soon as he starts a person can break their fast.

13. Making Dua

Many people don’t take advantage of making dua before they break their fast. This is one of the three times when Allah accepts a person dua.

14. Last Days of Ramadan

Many people make the mistake of spending the later part of Ramadan preparing for Eid, neglecting Ramadan. This is incorrect and these people lose the concept of what Ramadan is about.

15. Manners

Some people think Ramadan is just about refraining from eating and that it is nothing to do with one’s behavior. In fact we are supposed to control our tempers and badmouthing more during Ramadan.

16. Wasting Time

People often waste their time. They tend to sleep the whole day and doing nothing. Ramadan however provides us opportunity to take advantage of this blessed month by doing more worship.

17. Fasting While Traveling

Some people travel much during in this month thinking they will have to break their fast while traveling. This is in fact optional. If someone wants to break fast while traveling one can (with making it up later), otherwise one can continue fasting.

18. Swallowing Saliva

Some say you cannot swallow your spit during Ramadan. This too is false. However you cannot swallow mucus that has entered your mouth.

19. Using scents

Some say you cannot use scented oils or perfumes during Ramadan. This too is false.

20. During Ablution

Putting water inside nose and mouth during wudu would break fast is another wrong perception.

Source: Ummah.com