Swgoh farming flowchart

The Guild Store is a little tough to plan around, since what is available will rotate every 6 hours. This can make it tempting to dump Guild Tokens on whatever is available immediately, but I recommend against doing so. Stockpile those Guild Tokens, and focus on 2 units at a time, only buying shards for those 2 units as they show up in the store. If you finish one of the two, focus on the remaining one before moving on. This'll give you a stockpile of tokens to spend on the next recommended pair.

Gear is also a main use for this store. Only purchase gear if it's applicable to the specific squad you're working on, and if the recommended characters are not presently available.