The first act of a doctor is to know the problem of their patient. They should be able to diagnose the problem properly, no matter how many tests they need to carry out on the patient. Knowing the actual problem and its stage can help the doctor prescribe the right medicine to their patient.
Generally, doctors start with prescribing less powerful medicine, as high potency medicine can lead to different problems for the patient. This is particularly true if the patient has allergic conditions as high potency medicine can lead to any severe reaction.
Start with prescribing a a dose of low potency. For example, you can ask the patient to take the drug three times a day, and its potency should be minimum. If the patient shows improvement you can change the dose, especially if you are cleared that the does not have any particular negative reaction on the patient.
Be careful in making a choice if you have more than one drug available for the same solution and it is better to go for the one that works effectively. If you need to prescribe the medicine with some other medicine, be careful because sometimes prescription of two drugs at the same time can work against each other and can lead to severe reactions for the patient.
If the cheaper version of a drug is available, then do not prescribe the expensive one. Often, people find it very hard to service the medicine bills, especially if they do not have a social protection or health insurance. A consideration to the financial health can be a factor in prescribing medicines to your patients.
Do not indulge into branding of the drugs, as one drug can be manufactured by more than one company. You as a doctor should give preference to interest of your patients rather than the manufacturers and whatever brand of medicine works better you should prescribe that to your patients.
Further, in the beginning prescribe the medicine for about a couple of days or three days as maximum and gauge the progress to check the drug's effect on the patient. Do not prescribe medicines for weeks and months without any reason. Inspection of progress is also your responsibility as a doctor and you should fulfil that effectively.