Hi , i would like to know if there is a good way to start on a low server
for example , should i make a dwarf for spoil or a buffer
and what class should i use in order to lvl up fast and farm good?

Well from what I've learned over the last half year of brushing up is that if the server has been running for a long amount of time, don't try to do too much yourself. Depending on chronicle, early chronicles pay off more in terms of doing things solo compared to the later ones, where being in a party shifts slowly from being the preferred way of doing things to the mandatory way of doing things (this shift is also very apparent when going from low to high levels).

Buffers only if you're VERY certain you can consistently get a party or else as a dualbox character to help your other char(s). Dwarves are always nice to have, but personally I haven't had too much success in making money with them, the main perk of having a spoiler is being able to gather a lot of pesky materials yourself (for example for quests like "An Obvious Lie" or the Formal Wear ones which require a lot of specific mats which would cost you a fortune otherwise). Generally a server's market seems balanced out on the difficulty of getting mats compared to what their prices stand at.

And you should not lie to yourself in going for a class to 'lvl up fast and farm good'. Play what you enjoy playing as a main, and do the support on the side. If you need a specific class for farming good you can always dualbox one or sub it.

Just my 2cents.