Level 8? You mean mission 8? LoL, I can't remember, is it the defending the Hill mission?

it's capture and defend correct?
you will need to set up defenses wide.
build a lot of tank traps in all the openings but leave one open so that the stupid AIs whould send their tanks from the opening and die like shit. aim 2 AT at the openings.
remember to keep your ATs away from each other until you have taken care of the nebelwelfers.

you need to have at least 2 shermans ready before you take over the square. use infantries+snipers to clear and capture other points around your objective, and set up some mines and maybe defensive stuffs around them. barbwire does the job well.

keep your calliope on the small island and use his rocket as a last resort if you cant hold on the the square, it is to save it from being captured.
you will need at least 1 sniper and 4 ATs to do this defense job right, you will need at least 1 Halftrack with quad cannon armed with 2 shermans to go in and out, with engineers setting up something like a repair station on the small island or at corner of the fuel point next to your objective.

it's pretty much it. just adjust your defenses. remember this game is to be aggressive and go out and attack, sitting at your objective usually gets you killed pretty quick.

try to use your tanks and quad can to ambush the axis when they are on their way to the square. do a hit and run, it will hellp your defenses very much.