Apologies if you know this but it's one of those simple things that often pass one by.
If you get heel lift on your boot (which can cause blisters or hot spots) you can help reduce it with your lacing. When you reach the 'bend' in your boots rather than just carry on criss-crossing the laces do an overhand knot (like the first part of a bow) and then again for the next set of hooks up. This will help hold the boot steady around your ankle.
When you get to the top and are ready to tie the bow put an extra trun into your overhand knot. This will help hold the laces in place while you get tied, keeping the tension on the laces and holding your boot firm.