Most preachers develop of preparation cycle and rhythm. Perhaps it takes five days from start to finish (maybe with an extended period for collecting any interesting tidbits from the point the series are planned). Perhaps you have an eight or ten-day cycle. Perhaps you only preach periodically and so take two or three weeks to study the text and shape the message.
Consider having a slow cooker bubbling on your desk. You could take that literally, but I mean metaphorically. Select a series or a sermon that is several months away, set apart 15-30 minutes a day and work through the text nice and slowly. It allows you to take your time with original language work, whatever level of ability you have. It allows you time to peruse, ponder and pause over the commentaries. It allows you to gradually formulate main ideas of sections, outlines of messages, etc. It allows you to make notes of specific support material.
All the things you may have to rush through in a normal preparation cycle, you can do well with this approach. What’s more, that slow cooked sermon and the textual study that underlies it may be more of a feast for your soul than some of the study and sermons you do at your normal pace in the meantime!
My messages are seven months away. The cooker is on (and I get to enjoy learning Logos 4 at the same time!)