[That_Guy]

Okay, first of all, you pintal stubbers are the #1 choice to throw on a tank. Take a look at your options. Its either that or a mounted storm bolter. storm bolter has higher AP, but less range and only fires twice, while the stuber fires at longer range and fires three rounds. It may have less AP, but the well seasoned guard player knows that sending a tank up close is sending it to its doom. Besides, the more common foe is a MEQ (Marine Equivalent) player, so the ap isnt all that great anyway. Think of how many possible shots you could put out on a chimera with multi laser, hull heavy bolter, and the stuber. 9 shots of realativly high streangth. THat is what guard is all about, massed firepower.
I would only put Stormbolters on the demolisher, since it will most likely be up close a personal anyways.

Do's and Dont's

For your own health, don't focus entirely on one thing. Your gonna lose. Alot. Balance is key to winning. Keep this in mind when useing regimental doctrines.

Spending hundreds of your points on command is useless. Under some circumstances, the command may never really see combat. Give the group a cool trinket or two, then move on. You can use the points towards a whole new squad instead.

Stay alert. When the enemy changes his strategy, you better be ready to follow suit the next turn. This goes back to the balancing act. Balanced armys will have no problem adapting the the enemys diffrent tactics.

Its really hard to give pointers when I have no Idea what you might be trying to do. Do you have any personal prefrences to how you want your army? Mabye a sample list of units?