Assuming a multi-day auction, and assuming that there is an intention to purchase say X amount of the good that is auctioned (whatever that is) ... I would contribute once per day, same amount of X/N, over a long period of N days.
As the pattern is easily spotted, I would also signal it by announcing my intention.
What I'm not sure about is whether to commit to the signal or not. There might be some reasonable circumstances where I should not commit - e.g., where it is clear that the secondary market is cheaper.