Garhwal starts out in a difficult situation, with the mighty and often hostile 德里 to the south and the Himalayas blocking expansion to the north. The player is often faced with the decision to support either 德里 or 章普尔.
科奇 and 蒂鲁德 start out friendly and can be allied from the start in most cases, one might refrain from royal marriages though as they will likely be subject of future conquest. With initial alliances secured Garhwal can work to improve relations with either 章普尔 or 德里, or any other friendly major power in India depending on the situation. One can instantly fabricate claim on 坎格拉 and declare war as soon as they have a claim, the war should be easy as Kangra often finds itself without allies. After the war Garhwal's development will be nearly doubled, just make sure your armies outnumber the Kangra army as you will be attacking into hills. This will open up possibilities for expansion westward, into 克什米尔 and 拉达克, but make sure to keep out of the way of 帖木儿 for now and take no province they have a claim on as they start out very powerful and will usually attempt to expand into India.
Next Garhwal can take on its eastern neighbour, 尼泊尔. They also usually find themselves with few or no allies and together with 科奇 and 蒂鲁德 the player should be able to beat them. They make a useful vassal, but take one or two provinces to keep them loyal. By now you should be able to secure an alliance with a major power, dissolving the alliances with 蒂鲁德 and 科奇, declaring war and giving their provinces to your new vassal 尼泊尔 might be for the best as rapid expansion is desirable.
Now the player has to choose between expansion into either one of 章普尔, 德里, or possibly into 孟加拉. They will most likely rival each other, so rivaling one will make the other friendly. Keep an eye out for a good time to strike, such as when 德里 is at war with 帖木儿 or 章普尔 with 巴赫曼尼, and call in your ally and take as much land as you can cope with.
Another option is to expand into 西藏, however both Tibetan states are tributaries of 大明 so make sure Ming is busy with other wars or become a tributary yourself. However, the Tibetan provinces are of wrong religion and rather poor, so carefully consider whether or not they are worth it.
Keep an eye on what is going on in southern India, usually either 巴赫曼尼 or 毗奢耶那伽罗 will become a dominant power in time and can stop the player's expansion dead in its tracks. This should obviously be avoided so keeping them both about equally strong until you can defeat them should be a priority.
In the west 帖木儿 will most likely fall apart, meaning expansion into Persia is possible. In the rare cases where they survive without 波斯 and/or 阿富汗 gaining independence they can still be defeated, as they are a horde their units will suffer penalties if fighting in rough terrain, such as hills or mountains, and conflict with the 奥斯曼 will mean they have less time to focus on you.