• There are various dimensions in a job to be motivated by, not just what you get paid. Your training period, kind of work, kind of team, and the other things you value, like work-life balance, for instance.
• You also need to understand what the company values. Salary is a recurring cost, that increases over time while being a subject of gossip due to inequality. A joining bonus is a one-time expense and isn't public.
• There are other perks to negotiate for, like relocation bonus, which can be easier to arrange.

Simply asking for more may be a put off for recruiters, but providing an unobjectionable and sympathetic reason is a good strategy.
Example: I want to buy my own house within the next year, what can we do to improve the salary?

Asserting Your Value: Assert yourself by being confident, without boasting, or providing some specific metric that may be proven wrong. It helps to anchor the statement earlier and gently repeat it so that it is within the already established negotiation points and not something out of the blue.

A prospective employee can refrain at first and talk about being a good mutual fit and being able to learn, rather than mere figures.

If pushed towards a number, you can quote the average industry salary in your domain, as a starting point. You can also mention your current (or past) salary as an anchor point, starting the negotiation.

• Once an offer is out there, Be polite and mention your best alternative offer, while expressing your desire to work with them. 
• Do consider your other offer, any leverage you may have and your earlier calculations. 
• Provide a valid reason in case you want to ask for a better salary.

Recruiters spend thousands of dollars on the recruiting process, and won't reject your profile or take away anything from you if you negotiate. They have already invested time, cost, and energy that may go in vain if you are not accepting their offer.

Know that it is perfectly fine to negotiate and companies are more than willing to negotiate with you.

Having an alternative, a second job offer with you makes your negotiation game stronger, as the employer knows that you can simply walk away. Having the offer from a prestigious company also strengthens your perceived market value.

Having a BATNA (Best Alternative To a Negotiated Agreement) provides you with confidence, based on how strong the employer perceives it as well as how you perceive it.

A job negotiation is preferable in person or on the phone, as compared to the impersonal and cold feel of the email.

Talking on the phone provides you with an opportunity to build a connection so that the recruiter understands you and your motivations, while you have a better grip on their motivations.

If the job negotiation is on email only, be direct and honest. Email lets you strategize your words carefully.

Negotiating doesn't mean arguing, being stubborn or creating a scene. The best negotiators are empathetic and collaborative, pursuing a mutually fulfilling solution. A good negotiator can bend the rules, question assumptions, looking for creative ways to widen the terrain of negotiation.

A job negotiation has many dimensions like salary, work-life balance, bonuses and many perks that make or break the deal.