Hello.
If you are in class 12th and you want to go for civil services then firstly you will have to be eligible with this.

• for civil services a candidate must have qualified with a bachelor degree.
• There is a special age limit for each category candidate.

if you are doing your intermediate in arts stream then it is a fantabulous thing for you because the rest journey for civil services will be easy for you, for the preparation you can join test series you will have to read newspaper on daily basis, you will have to be a aware from the general knowledge also.
Best of luck.