A visa refusal can be obtained for a variety of reasons. Some of them depend personally on the tourist (incorrectly executed documents, unreliable impression), while others depend on the consulate itself (a “harmful” worker was caught, the country's policy is such that the consulate denies visas). It is impossible to insure against cancellation.
Before submitting documents, you should realize that the basis of the practice of issuing visas is the so-called presumption of guilt. If one country does not allow residents of another country to freely enter its territory, it usually expects some special behavior from them. For example, illegal migration or propensity to criminal activities. To protect against this, visas were introduced. Therefore, the consular officer considering your documents is pre-set against you. And your task is to convince him that everything is in order with you, that you are a trustworthy person who can be allowed to enter the country.
It is very important to convince the consulate that your visit is economically beneficial. It is for these reasons that it is recommended to demonstrate large sums of money on the account, book expensive hotels and show salary certificates, which indicate a decent salary. If everything is not so simple with the certificates, then it will never be superfluous to put a little more money into the account before making a statement (unless a statement is required that reflects the movement of funds over the past months). A person's lack of money is one of the most common reasons for refusing a visa.
Another important point is to prove that you have no criminal intentions. Suspicions of a visa officer can appear after anything, many countries bring violations of the law by tourists to the database, so a person's criminal history is easy to check. For example, if you once did not pay a fine for incorrect parking or a ticketless passage, then later you may have problems obtaining a visa for this country. The same applies to those who violate the terms of stay on a visa. Likewise, those who have been expelled from the country for illegal employment have little chance of getting a visa the next time. If you have any violations, try to pay off them: pay all fines and debts.
An incomplete package of documents is a very common reason for refusals. Sometimes people forget to include insurance, hotel reservations or airline tickets. Someone does it deliberately, hoping to "give it a ride". But getting rejected is pretty frustrating, so make sure to double-check before submitting.
A very important "headache" for employees of all visa services is the identification of potential illegal immigrants among the applicants. Some countries are particularly corrosive in this regard. Sometimes it is better for them to prepare a little more documents so that no one doubts you for sure. If possible, show marriage and childbirth certificates. In the case of valuable property (real estate, car, securities), it is useful to show the documents for the property. For some countries, it may even be useful to show your credits so that the consular staff are sure that you have connections with your homeland. Even the photos of your pets that are waiting for you while you travel will be carefully considered by the British Embassy.
Incorrect information is a common reason for visa refusals. Some things are revealed later while you are traveling. For example, if it turns out that you have not stayed at the booked hotel, you may have problems with your next visa (happens with Schengen countries).
There are also informal reasons for refusals. For example, the applicant looked suspicious in a personal interview or when submitting documents. It also happens that an employee is in a bad mood, and he strenuously finds fault with requests. Unfortunately, the human factor is also present in this matter.