To earn infinite XP, begin "Raid on Oscorp." After you go through the air vents, you'll see a skippable cutscene and then have five enemies to deal with. Use stealth to take down the first four. The fifth can be handled any way you like. Next, pause and choose to restart from your last checkpoint. You'll keep the XP you earned and return to the point after you left the vent, allowing you to fight the same five enemies again. Repeat as needed.
The southernmost Russian hideout is the easier one in which to get the "Sneaky" achievement/trophy. - It should be noted that if you clear a hideout, you can't return to clear it again.) You need to clear the hideout and reach your objective in this case, the container on the ground without being noticed. The guards' awareness level is indicated by a meter in the upper left corner of your screen. Make your way along the ceiling with Web-Rush and take care of the guards without letting that meter increase. If it gets above zero, just restart.
I'm on a Roll Achievement/Trophy
The "I'm on a Roll" achievement/trophy is more easily earned during a combat challenge. Combat challenges are accessible from the arcade machine in Stan's Comic Book Store. Fight the enemies in the challenge normally, until only one remains. Then, use Web-Strike on the enemy until you get a combo streak of 42.
Friendly Fire Achievement/Trophy
For the "Friendly Fire" achievement/trophy, you'll want to pay attention to the levers in the boss fight room in "Maximum Carnage." If you stand beneath a lever, you can pull it when Carnage is near to shoot him with fire. During the second section of the battle, keep an eye on Carnage. When he jumps up the wall, activate all of the levers. Attack Carnage with a Seismic Blast to force him into the first. If you can do this three times, you'll get the achievement/trophy.
Aerial Break Achievement/Trophy
The "Aerial Break" achievement/trophy can be tricky, but you can get it at the start of the mission "The Kingpin of Crime!" You'll see a tutorial to help you fight the armored enemy. Disable its armor and then use your Web-Strike.