Best way to open a Iphone, without using a mini screwdriver?
Get the right tools, or, better, take it to someone who has experience with phone repairs. Consider: If someone else damages your phone, they have to make good on it. If YOU damage it, You have to take the loss.
Take it to someone with the proper tools.
There is no best way, and doing so yourself could void the warranty.
The best way is to go and buy yourself the right tools. Do you really want to damage your phone because you can’t be bothered to buy some cheap tools??
Did you read back your question? You're asking what's the proper way to unscrew a phone if you don't have the proper tools. There is no proper way to unscrew something if you don't have the proper tools. You can try work arounds rather than the proper tools, but the results cannot be assured. You can buy a set of mini screwdrivers for just a few dollars. And they last forever. So get them, then do your iPhone in.
Tablet plastic parts and screens pop out and separate. Dragon Touch did not have any screws probably.