Welcome to the Imperial Guard Strategies page. I hope that these will prove interesting.
The key to winning with the imperial gurad does not have to be tanks. You can use you troops(with veteran abilities) to make due without those great hunks of metal that carry those huge guns. Well, how do you do it? You have to decide which squads will do what job on the battlefield and equip them accordingly. I will not go into the veteran abilities but i will leave them to your discretion. You will easily be able to handle all aventualities with just one tank (leman russ is my preference).
Your officers are the best thing to keep your troops in the fight with their high leadership they will help to support your squads against assaults. The best bit to di is to split up your army so that you have a ratio of one command squad or command HQ for every two battle line squads. The command HQ should be given a battle standard and placed where you think your enemy will break assault your lines. If you place them in good cover then you can be able to withstand most close assaults and bea able to walk away from them.
You best bet when choosing squads is to separate your troops into a "hammer" and an "anvil". The anvil will be made up of battle line troops, the cheapest you can get with some ratling snipers to help support them. This is where you heavy weapon squads will go when you choose them. Your command HQ with the colonel/captain and the battle standard will go right in the middle of all these troops. This is where they will do the most good. They will support your "agressive defense" and will lend a hand in the HTH phase.
You "hammer will be made of your tanks, as well as storm troopers and ogryns in Chimerra trnasports. They will come onto the board from reserve and will crush the flank of the enemy. Then you can continue into a pincers movement with your agressive defense or "anvil". This very often brings you victory.
Tanks. What do you do with em. Pick them correctly. if you knwo youre going to be fighting among dense terrain then take the fire spewing hellhound. If not then the leman russ and the griffin are always welocme. The basilisk is not recommended because of its extreme range and general disusefulness. Tanks are a great asset but they can give away horrendous amounts of victory points. That is the major downside to them. But you can help keep them alive by using vehicle upgrades but beware, they increase the cost of the vehicle and make it worth even more victory points.
Good luck with your battles for the imperium and may these help you win a few.