1 Look at the timing of the tender - if it is one week from the start to the end of the receipt of bids and the tender is not too long, it is a very bad sign. There are 2-3-4 weeks, or even more, for greater integration. A week means who has already done everything (perhaps not only the documentation, but the entire tender).
2 Platform and requirements. If the tender for .NET, and you have PHP programmers, everything will be sad, it's already clear. And in 99% of cases, the change is not that of the language, and even the platform (say, from Laravel to Symphony) will not work.
3 The customer's presence. Approximately 3% of tenders have the option of "presence at the customer". It would be painful and expensive if you were 2000 kilometers away.
4 Sending on paper. We used to think of it as a block factor, but not after comparing the conversion. You can win on paper, even though it looks strange in the age of electronic platforms.
Keep in mind that sending and delivering an envelope takes 1-2 days.
5 Documentation. If it does not exist, and a huge system like personal cabinet is described on two pages (we had it), it means 80% that the system has been developing the same contractor for years, and the best thing that awaits you is to take it in a row after winning.
Treatment: see who has won this project/contractor before (where to look - in the next post).
6 Here is the pain for everyone. MAKET. Draw me a layout. Or two-5-10.
We have a simple sample: we 8 times drew layouts for free, and two times - for money (even symbolic, like 20 thousand rubles). We flew 8 times, and both paid times - got contracts. We do not draw for free anymore.
7 See item. 5 - even if the tender is perfect, if it is an accompaniment/support, it is worth seeing what it has done before. If the same people have been doing this for years, this is a serious reason to think about it.