The Prince flew in the face of a prevailing theory that a virtuous prince would rule most successfully. Instead Machiavelli advised that too much virtue could be the downfall of a ruler and that rulers should instead cultivate the following characteristics:

Instill fear: This characteristic was partially to keep the common people from staging a revolt but also meant to keep potentially powerful rivals or rivals groups from plotting to undermine or overthrow the prince. If you are perceived as ruthlessly vengeful, people will be less likely to challenge your authority. It is better to be feared, than loved, said Machiavelli, if you want to hold your power.

Take good care of the common people: No amount of elite or army support will maintain a prince who does not have the people on his side. Make sure to take care of the material needs of the common people so they will stay loyal to you and be willing to fight in your wars, if need be.

Be careful with money: While you definitely want to take care of the common people, you do not want to go overboard. It is better to be a miser than overly generous. It is important to keep the state solvent: running out of money means raising taxes and leads to unpleasantness. But money acquired through conquest can be spent freely. 

Be publicly virtuous: If it makes sense to be ruthless and instill fear among your fellow courtiers behind closed doors (and while it does not really matter what you do privately) publicly you must show a virtuous face to keep the support of the people. While you sometimes must abandon virtues like generosity, loyalty, mercy, honesty, and religious piety, it is best if you can seem to embody them. A prince sometimes has to sacrifice good reputation to keep power, but it is best to avoid that path. 

Be a strong military leader: A main purpose of a prince is to protect his territory and his people. A prince who is perceived as weak this way will be despised. 

Be willing to break promises: A prince should appear consistent but nevertheless be willing to go back on his word when he needs to. 

Be able to think for yourself: This kind of intelligence is vital to a ruler, who needs to understand things for himself and to understand what others are thinking. A ruler must not rely on advisors.

Be able to judge people wisely: A prince should surround himself with wise advisors who will tell him the truth, not flatterers. A prince surrounded by flatterers will not command respect.

Be hardworking: Indolent princes lose their kingdoms and have only themselves to blame. Only half of what happens to us is through "fortune" or fate: the rest is due to our own "sweat" and character.

Be a risk taker: When the going gets tough, go out boldly and be willing to face "fortune" head on and strike her down. Fortune (fate), he says, turns against people who do not take matters into their own hands.

Be willing to cultivate foreign allies: This implies going to war, but whether you win or lose, you will keep your allies and that can only help you.

The Prince by Machiavelli was addressed to Lorenzo de Medici, who was a member of the ruling family in Florence, as a gift. Although your question asks for ten characteristics for a prince to rule successfully, understand that several of these characteristics overlap one another. Therefore it is important to review the reference link below for further clarification:

1. never leave anything to chance

2. organize the military without mercenary soldiers because they fight for money, not loyalty

3. it is not necessary to reward loyalty with loyalty

4. morality and ethical behavior are subject to change

5. the perception of the prince is more important than actuality

6. appearance matters

7. deception is acceptable and even necessary

8. promises might have to be broken

9. keep your friends close to you, but keep your enemies "closer"--meaning know what your opponent is doing at all costs

10. to keep power a prince fully accepts the concept of the ends justify the means