Just use extra gold for walls
My strategy is simple. I try to keep the defenses being upgraded at the same time, not more, not less (have a lot of catch up to do after a premature TH8).
Usually it means one defensive upgrade (sometimes 2) initiated each day. I usually play just a couple of hours in the evening and that is about 10 raids per day. I simply keep raiding for this 2 hours and try to get as much gold as possible. Then when I am done for the day I leave aside what I need of rthe upgrade scheduled for that day, max walls with the rest, then start the upgrade and then go to bed in peace knowing that there almost no 0 gold left in my storages.
Next day, rinse and repeat.
Have been going great for me so far. 40 days ago I was a premature TH8 with TH4 defenses and walls, level 3 troops. Now I have maxed mortars, level 7-8 archer towers, 8-9 canons, 4-5 WT, 2/3 of wall to level 7, level 5 barbs, archers, giants, 5 lighting and rage spells, full army camps, 1 level 4 dark barracks (the other is still level 1), maxed DE drill and storage, level 6 BK, 1 level 8, 2 level 9 and one level 10 barracks, etc. I think that is a good progress.
My hidden teslas are still level 1 but I was intending to max the splash defenses first and then switch to HT.