Do you follow any framework, or guidelines when writing/sending sales cold emails?

Yes, it makes the writing process go faster. For example, AIDA (Attention, Interest, Desire, Action). Think of it like throwing a party. You need a killer invite (that's your subject line). Then, get them curious about the event (that's the interesting bit about their problem). Make them really want to come (that's where you show them how your product/service is the answer to their prayers). Finally, tell them where and when it's happening (that's your call to action). Or another one. Before-After-Bridge (BAB). Show them a picture of their current situation (the 'before'). Then, paint a rosy picture of life with your product/service (the 'after'). The bridge? That's your product or service that helps them cross over from the 'before' to the 'after'. There are plenty of formulas like this. Find the one that suits your use case.