If you have a full service broker, the more business you do with them, the more likely it is they will give you larger allocations in desirable stock.
If you'd prefer to go through public offers, or intermediaries like OnMarket - which won't have all deals, and even fewer desirable ones - then it helps to have a few different HINs. You might consider a secondary/third online brokerage account, either with the same provider, or another altogether. That way you can bid under different accounts. Sometimes they will say duplicate account bids get deleted, but haven't come across this happen yet. If anything, each bid is more likely to be scaled back.
