I only build level 5 and 6 of admin in my provinces, and I only build admin buildings if the base income per year in the province is over 5. I get usually as many loans as possible to build level 4 army buildings and 4, 5, and 6 of admin. I do not build usually market buildings.
I do always get another one if my final monthly income is 0, if I would put my army in a 100% maintenance, and I have militar or admin points available to construct a new building.
I quit building infrastuctures when the neighbour bonus is -10% in admin, and -5% in militar.
But when the third idea is available I get the administrative ideas, so I wait a little repying some loans.
I do not get loans before if possible, and I always try to change the amount of the loan -get a new loan, with a higher amount, to substitute the former one-.
The normal amount of loans in a normal game is like 40 or 50.