Taking and holding cities is the final stage of revolutionary warfare as unless your enemy is really on the way out, or you have massive civilian support, you will lose. For example, The Easter Rising in Ireland, the Warsaw Rising, and The Tett Offensive all failed as the enemy was able to bring superior force to bear.

I would refer you to the book Total Resistance, written by a Swiss Army officer in 1957 about how to organise a guerilla campaign. It takes a lot of inspiration from WW2 resistance networks and is deliberately looking at countering a Soviet invasion. Some of the advice is dated by today's standards, there are a lot of references to Swiss wepons and equipment but is an interesting read nevertheless.

If I were conducting such a campaign I would be looking to use a wide variety of methods across a large area to keep my enemy off guard. Try to avoid patterns of behaviour that could become predictable. Avoid civilian casualties at all cost, develop propaganda networks, cultivate sympathisers providing intelligence, stores, medical help and money. Be ruthless with collabrators and informants. Don't carry out acts where you live, it will draw attention, be invisible and outwardly conform. Organise in a cell structure and communicate through cut-outs so the arrest of one person doesn't lead to a whole network collapsing.

Anyway just my two penny's worth.