zendesk. They have a pricing scheme for start-ups: http://www.zendesk.com/product/features/startups/

always follow up a connection request / connection invite with a phone call. ALWAYS.

I could help you. Worked with a friend on a sales funnel a few months ago using best in class practices. My rate is very low.
Looking at your website, it seems to me you don't have an onboarding process. You're just showing the shirts. Not underlining what you're good at and so on so forth...

if you want we can do a quick call. Afterwards, I can provide you with a whole plan / model

Hi, I have supported some companies in a similar situation, so pretty sure I can help. I'm answering backwards:

(2) You should create somekind of CRM solution ASAP. There are various products out there, some free, some very cheap, some very expensive. The truth is that you're hemorrhaging money if you don't do something asap... Have you calculated how much revenue you have lost, already. If you haven't do so, it will give you a sense of urgency!
(1) You also might need some advice on your whole sales cycle. Create a sales process that allows you to start disqualifying leads. Maybe you need more leads, maybe you need more people, those are all answers that you can only start addressing once you have some kind of rudimentary sales process in place.

Willing to run you through what you need to get fixed (steps, plans...). Ask yourself, what is the point of running a b2b startup if you are only spending money on marketing and don't have any revenue... Always available for a call!

I would say ... "linkedIn" but then I would be selling my own products, which is not necessarily what I like to do on Clarity... :D

I would suggest setting up a LinkedIn Group and then sending out individual inMails to experts. You want to craft your inMail in such a way so they'll want to participate in the group. You should be able to find the right experts by leveraging your own network or using filters to find the people you need. Make sure you have some running threads/topics in the group. If there is nothing to talk about your new found expert will quickly walk away.

It all depends what kind of deals you want to attract. It is healthy to have a good mix between smaller and bigger deals. Bigger deals are often more time consuming and from a risk perspective quite dangerous. I have seen many companies go bust because they lost their biggest client. Revenue is a bit like a layercake. You want some bigger deals and lot's of smaller ones. The bigger deals are your spungecake layers and the smaller ones are your filling.

I would therefore suggest to pay out a fixed fee whenever a small deal is signed (this will incentivize your salesforce to sign the small deals that you need to decrease revenue volatility and not waste their time on very big deals). At the same time you do want to reward signing bigger deals. All deals big and small should therefore count towards a set revenue target. The trick here is to implement ramps, decelerators, and accelerators. No compensation is payed out when all deals combined remain under 60% of the set target, from 60-100% of target your compensation follows a linear function, from 101% you pay out following an exponential function.

I'm happy to schedule a call with you to discuss all this in more detail. Do not hesitate to contact me.