What should i look for before downloading a torrent file ?

First of all, the number of seeders is most important- a seed is someone with the complete file who is sharing it. A leecher is someone like you, who doesnt have the file and is trying to download it. Health is simply a simpler way of estimating the download speeds + number of seeders on most torrent sites, but it really depends on which one you're using.

The first thing I look on is the seeders number. This for me is important because small number of seeders means lower download speed. But, keep in mind that the upload speed or the seeders play a role too. The second thing, which is for me is important, is the comments. Comments from people who have downloaded the file you are looking for is crucial as it gives you a better view of the file. For example, is the file has virus? Is it worthy to download the file? And so on. Sometimes, some people might suggest you other torrent. That's all I think. Have a good day!