Covers: Laser weapons are most effective against optics (biological or electronic) and living tissue (because it contains water that explodes upon being heated). Other things can be also destroyed by heating. Anything that is resistant to heating and melting (such as earth) will provide very good cover. Laser travels in a straight line, obviously. Your infantry will still need mortars and grenades to be tossed over cover. Fog, smoke, and dust will also provide very good cover and will be extensively used.
High ground: In modern warfare, this is less important since your infantry probably won't be bayonet charging uphill. Still gives you a better view if you do not have drones overhead.
Collateral damage: Since the "projectile" travels instantly (well, at the speed of light), you are only hitting the thing in your reticle.
Explosive objects: Can easily be made to explode with the laser, very vulnerable.
Small areas such as rooms: Depends on how small you can make the laser rifle. Also, your soldiers will not want to be waiting for the rifle to recharge with an enemy 3 meters in front of them. 898
They would probably have their conventional firearm drawn in close quarters. Hand grenades remain the workhorse for clearing rooms.
Body armor: Eye protection will be of supreme importance. A high powered laser shot to the eyes will permanently blind and instantly incapacitate. Laser reflective materials are available and will be used on body armor. Perhaps something akin to the smoke grenades that tanks use for cover.
Suppression tactics: Since the "projectiles" are invisible and make no noise, and your version of the laser rifle seems to have a horrible rate of fire, you'll probably have to use something else for suppressive fire.
Wounds: No exit wounds. Horrible burns. Blindness.
Snipers: Laser rifles probably not well suited for this application at very long ranges due to blooming and dissipation but if with your technology you can miniaturize something that the US Navy is using to an infantry size weapon, there are advantages: Not effected by wind or gravity, instant hit, no muzzle flash. At mid-range, snipers will probably use your version of the sniper rifle but switch to a projectile weapon for long range. 347