As you can see, the region I want to expand into is dominated by four superpowers: the Ottomans, the Mamluks, the Persians and Morocco. The Mamluks, my first big target, have a 37k army (compared to my support limit of 12); it's mostly infantry. Their land tech is 6 to my rapidly advancing 4. They're still tribal, and their ruler was inaugurated in 1451, so I'll keep my eyes out for a tribal succession crisis. The strategy will be to try to lure them into the deserts of Arabia and southern Egypt while I siege the high-value provinces on the Mediterranean.
Meanwhile, though, I want the Jalayrids as a vassal - they control some high-attrition provinces where I'd love to see the Mamluk armies sit for a while. They're guaranteed by Persia, so I declare war on their ally Kazakhstan, bringing in my vassal Yemen on my side, and Qara Koyunlu and the Timurids on theirs.
The war lasts until December 1477. I get military access through Persia (which Qara Koyunlu also has) and take advantage of their lack of forts to sack most of their land while they're on my territory. The result is a nice tribute of 1775 gold. Jalayrids vassalizes in December 1477. The next month, the old fart in charge of the Mamluks finally dies and they get a succession crisis.
Here's the situation as I gear up for war:
They have 30k infantry and 2k cavalry. I have 8k cavalry ready for duty plus my 4k in the south rebel-busting.