Followings are the some tips for preparing of HAS
For Paper 1 (General Studies): Read one good news paper daily.
Watch news on Tv daily
Buy himachal map and understand it
Become aware of day today important affairs/news of national & international importance.
Read general knowledge books (perticularly of himachal and India), Read historical facts.
Prepare 10th level Social Studies & Science.
For Paper 2 ( Aptitute Test): Prepare 10th level mathematics.
Prepare from R S Aggarwal for reasoning.
Prepare for English
Language comprehension skills (Class X level).
Also refer HAS syllabus, for clear understanding and prepare accordingly.
Best of Luck.