Good tips so far. Well let's face it, you won't be a dps monster and sit on the top of the scoreboard without hakkon weapons and a fair bit of promotion. Hence for you playing squishy dps characters like archer and reaver might mean a bit of hard work and situation awareness during the matches. Instead you could try support classes (that's what I did until I got my 3rd hakkon weapon and became more confident in NM).
First try Lego to see if you like him. Walking fortress + Counterstrike + Shield Wall + War Cry/Unbowed/Shield Bash/Payback Strike
You will be using your auto attack for the whole match plus shield wall attack cancelling. Pretty dull to be honest. But you will be very useful as a tank and holding the aggro.
You want some kind of guard on hit weapon (magehunter shield and the new lv26 1h sword) or walking fortress on hit weapon (e.g. the new lv26 shield and Hakkon sword)
You want as many mobs surrounding you as possible, keep your auto attack going and just don't worry about doing damage at all. Whenever you see your guard is empty or some mobs are going for you teammate, use Counterstrike. If you are starting to lose health and is on the floor then use walking fortress.
Next try Ele. Use firestorm as your absolute core skill. Utilise flashpoint passive to make it spamable. Keep barrier up but prioritise yourself if there is ranged targets aiming at you and flashpoint passive is on CD. Firewall is good, winters grasp is good, fade cloak is good. To be fair, pick any CC abilities or defensive abilities you want for the last two ability slots. Because if I'm honest, you won't be using them much if you are utilising flashpoint properly.
Pave your way with firestorm! Once flashpoint is on, USE IT! Try cover some melee enemies with your first one then stand inside it. If there is no ranged units targetting you, then great keep stacking firestorms on your feet. If there is a squad of ranged units aiming at you, then drop a firestorm on their head and move yourself into the new firestorm. Self barrier if the archers are already hitting you and you just used firestorm. Don't panic because your barrier will sure last you for more than 10 seconds.
Of course, if there is some mobs immune to knock down, i.e. pride demons, then don't run ahead towards them. Just don't panic as your barrier will keep you safe and let your teammates to deal with him while you keep supporting them by knocking everything else down.
Pro tip: more firestorms means more chance of crit. So you activate your flashpoint straightaway after that 10sec CD time. And more firestorms means more knock downs so you are safer. Sceptor of razikal is truely amazing for this play style since it has fade cloak on hit which will proc as often as you need it to be if you are able to sustain 2 or 3 firestorms active on the field. This gives you complete immunity to any attacks so you can cast firestorm more easily uninterrupted. If you take fade cloak as an ability then you don't even need barrier on yourself. You can afford to spend a couple seconds to barrier your teammates instead of prioritise yourself.