A thing to remember here is that these posts are strictly meant for the particular planet position. Like, today we are looking at Sun in Capricorn, so the description given here may change for you if your Sun is although in the sign of Capricorn but with conjunction with or aspected by other planets.

So, lets see what Sun can do in the sign of Capricorn. 1st lets see what these 2 things represent -

Sun represents Personality, King, Government, Father, Authority, Career, Top Positions, Ego, Self Esteem, Health, Education etc.

Capricorn is the 10th sign of zodiac belt, hence it represents many things related with 10th house of horoscope like Law and Order, Government, Authority, Organisation, Discipline etc. Besides it also represents World outside your home and people, Fear and Anxiety etc. Capricorn is consisted of next 2 and half Nakshatra, i.e. Uttar-Ashadha, Shravana and Dhanishtha. Capricorn is ruled by Saturn and that's why it represents Fear and Anxiety.

So when Sun is in Capricorn, these people abide by law, disciplined and rigid.  As Saturn is lord of Capricorn and represents law & order and fear & anxiety, these people are naturally fearful of law. As Sun is in the sign of Saturn, this fear becomes part of their personality. They don't want to take any initiative in public life or work life, as they are fearful of failures. They can have stage phobia. How long this fear works? Up to the time they enter mid-30s, after that they will start realizing their true potential. They will realize their right field of authority and won't be fearful about others anymore. Now, here Saturn's position is very important. If Saturn is weak, then these people will have real big problems in career and will always be fearful of how they do in world. If Saturn is strong, then also they will feel fearful but they will be able to over come that fear. Career wise, these people and also father can be in the field of Law, Government, Courts, Police, Army etc. Somehow, they have to deal with people.

As always, Sun's role in Capricorn can be effected by the nakshatra Sun is in. Like, if Sun is in Uttar-Ashadha Nakshatra, it will be somehow little comfortable as it is its own Nakshatra. If Sun is in Shravana Nakshatra, we have to look at Moon's position as Shravana's lord is Moon. Likewise, in Dhanishtha Nakshatra, its lord Mars' position is going to impact Sun.

Again, as discussed above, Saturn's position is going to decide ho Sun is going to behave in this sign, more so because Sun and Saturn are arch-enemies.