Here's a list of some class recommendations. It may or may not work well for you because it's really player preference but these class sets are usually reliable.

1. Rusher
Primary: PP90M1 / Kick / Rapid Fire
Secondary: P99
Lethal: Semtex
Tactical: Concussion Grenade
Perks: Extreme Conditioning, Quickdraw, Dead Silence
Summary: The PP90M1 is a very versatile submachine gun, ideal for short to medium range combat due to its high rate of fire and relatively low recoil. Rapid Fire allows you to win most CQC combat which but it may reduce long range effectiveness due to the recoil. The perk combination allows rushing while at the same time remaining undetected.

2. Assault
Primary: ACR / Attachments / Red Dot Sight / Kick
Secondary: P99 / Silencer
Lethal: Semtex
Tactical: Concussion Grenade
Perks: Sleight Of Hand, Quickdraw, Stalker
Summary: The ACR does good damage at all ranges and low recoil and the fastest reload time in the AR category. But the ACR will often lose in close-quarters engagements with SMGs and assault rifles with higher rates of fire. The iron sights are somewhat bulky, but usable at longer range which is where the ACR excels. The perk combination allows for a safe, balanced play style.

3. Riot Shielder
Primary: Riot Shield / Melee
Secondary: Striker
Lethal: Throwing Knife
Tactical: Concussion Grenade
Perks: Extreme Conditioning, Overkill, Steady Aim
Summary: The Riot Shield is a team weapon, meaning it requires teamwork to be effective. The throwing knife allows a quick and silent kill while staying behind the shield. The perk combinations are good for a player who wants to chase after enemies quickly.

4. Sniper
Primary: Barrett .50cal / Extended Mags / Speed
Secondary: MP9
Lethal: Claymore
Tactical: Smoke Grenade
Perks: Recon, Quickdraw, Marksman
Summary: The Barret .50cal does one hit kill to the head, neck, chest and stomach. The Speed proficiency is useful as unlike other snipers, the Barret .50cal slows you down. The perk combination is ideal for sniping.

5. Stealth
Primary: ACR / Kick/ PP90M1 / Attachments / Silencer / Rapid Fire
Secondary: P99 / Silencer
Lethal: Semtex
Tactical: Smoke Grenade
Perks: Blind Eye, Assassin, Dead Silence
Summary: The ACR is good at long range sneaking while the PP90M1 is good when in close-quarters sneaking. The Smoke Grenade allows you to get to an area to sneak or cover your escape should you be discovered. The perk combination makes you nearly invisible besides being seen by an enemy player.