I do not pretend to be an expert, but have intermittently grown bonsai trees for at least fifteen years. My techniques tend to be those which fit in with a busy life - minimalist. My tips are similarly aimed at securing healthy trees with a minimum of time and money. Know thy tree Make sure that you know, or very soon acquire some ID of the species of your tree. It will help hugely.
Trees differ widely and sometimes unpredictably in their requirements and susceptibilities.
Assume that your tree wants to live outdoors unless and until clear advice or your own knowledge says otherwise. More trees die from being kept inside when they crave fresh air, than otherwise. They may be pot plants but they are not usually house plants. Be careful though because many bonsai trees sold as such through garden centres are described as indoor trees. I think myself that these are more tender than is appropriate for a beginner.