Oh, "tang vietsub" probably means "increase Vietnamese subtitles". So the user is asking for 7 effective methods to improve or increase the number of Vietnamese subtitles in their content. They might be a content creator looking to reach a Vietnamese audience, perhaps on YouTube or similar platforms.
Including tips on timing and formatting of subtitles for readability. Using clear fonts, appropriate size, and color contrast. These details can make a big difference in how viewers perceive the subtitling effort. 7 nam o tay tang vietsub
Another angle: "tăng vietsub" could mean improving the quality or increasing the availability of Vietnamese subtitles. So the user might want tips on creating better Vietnamese subtitles, making the process more effective. They might be struggling with the technical aspects of adding subtitles or want to engage their audience in contributing subtitles. Including tips on timing and formatting of subtitles