Here's a few things I've come up with.
I space out payments for work in a way that helps me stay motivated, usually based on turning in drafts to the client. No work no pay.
I noticed that the time between turning in drafts gets shorter and shorter as the project goes on. Might be obvious to some but seems noteworthy.
I try to include an hour that the timeline is aligned to. For example, I include at the beginning of the timeline "After 5pm on all dates." I work a 9-5 and have a family, best to be honest about time limitations up front (unless you can double dip at your 9-5).
If there's any holidays approaching include that in the timeline to help explain large gaps. Thanksgiving is on Thursday so if turn in a draft to be reviewed on Wednesday I'm not going to expect to receive any revisions until the following Monday.
Any more advice or best practices for creating a timeline for clients? Yes I've read Design Is A Job. Yes I could Google it. I'd rather hear what you all have to say though.