Before you start applying for a particular visa, research it. Look at the criteria and whether you can meet them. Read about the required documents. Also, try to find blogs or guides on the visas. Our own visa guides are an excellent place to start since they are comprehensive and easy to understand.
The more you know about the visa you want to apply for, the better. You will have more knowledge and be prepared for the application process.
Besides looking into the visa you want to apply to, look at others too. Maybe there is a visa which fits you better and you did not even know it existed. Maybe you were going to apply for a tourist visa, but find out that a business visa is more appropriate.
Finally, if you do not have any time to research the visas, you can hire a professional to help. Many people hire lawyers to clarify the visa process to them, and to help with the application.
No matter how you go about it, gather as much information as possible before starting.