Good advice has been given here already, but I'll add my buck o' five. I've been vlogging since July 2012 and am closing-in on 6k subscribers. So, given that, I can explain what I've done and you can see about applying it to your own experience. Like everyone, I started from nothing! :>
1. Since vlogs are videos that need editing and production, get the basics down like good audio (so people want to listen), interesting footage (so people want to watch) and keep interest so people watch your whole vid or at least most of it. The effort you put in comes back...and the details matter even if nobody mentions them specifically. 
2.  Be yourself and follow your own path. Do exactly the video you want to do, even if you're influenced by other skilled vloggers. Make your vids as long or short as you think is good, but make 'em interesting. There are arguments for both long and short videos, but John Woo is different from Stanley Kubrick. Both are going to make movies their own way and attract their own following (with overlap). Do you have footage to fill a 30-minute video? Then by all means, make it so. Is your footage really only appropriate for a 5 minute video? Then edit it down to that (with good pacing). 
3. Learn your craft. Better-editing means you're making the experience more-enjoyable for your viewers. Remove the pauses or 'ums' and 'ahhs' from your speech if you do that a lot. If you mess up your speech, say the line again and cut the misspoken line (depending on how distracting it is). Show the broad-strokes (but also details that make you unique). Have a sense of humor, but be sincere and be yourself. Some people like a mature vlogger, some like a zany nut, and many people will enjoy both for the same reason we watch different shows. If you're yourself, it's easy to maintain and nobody can be a better you than you. Be confident and know your topic in a way that works for you. Some people rock at extemporaneous speech but if you don't, rehearse a little or write bullet-points for yourself. Really, subs don't matter as much as producing each video the best you can. Quality vids get noticed and quality vloggers tend to attract attention. I just shouted-out one vlogger who had 6 subs. 6! Why? He's quite good at what he does and I thought he deserved it. 
4. Reveal yourself. People like to learn about the vloggers they watch. Not only does it draw them in, but it makes you distinct and unique from others. 
5. No fakery. Don't B.S. your audience. Don't use fake titles or make obviously fake videos billed as 'real'. Be genuine. The viewers will appreciate this. This kinda goes without saying. 
6. Love what you do. Vlog because you love it, and that will shine through. Get involved. Meet-with and interview other vloggers but also interesting people you meet. If you're not a people person you can still be successful, but it helps to like what you do. Meeting with other vloggers is something I thoroughly-enjoy (and meeting people in-general) so that's really helped with subs too. As your get yourself out there you become part of the community quite-naturally. Go to events when you can. Always respond to personal messages and comments! People want to know that you're accessible (especially as you get bigger) and they sometimes just want to have a little interaction with you, or might have a question (even one that's been asked 1,000 times). If you like your subs and you respond to them, you will be rewarded. Sometimes people sub to you after this interaction. Other vloggers (especially big ones) often like some interaction too, and this can lead to shout-outs, meetups, etc. 
7. Be interesting. I think a lot of this is solved by simply being yourself and being 'an open book'. If you hide everything, you're less unique. Did you crash and film it? Show that! Learn from it and even if you get trolled, people will appreciate you sharing this. 
8. There will be trolls. Based on your personality, you may argue with them, charm them into liking you despite their best-efforts, or block them if they prove to be endless cauldrons of abuse. The bigger you get, the more trolls you will attract (especially as you reveal weaknesses and imperfections). It's part of the game. 
9. Branding. My branding comes from the idea I had in 2005 to make a 'spacesuit' out of my leathers, 7 years before I started vlogging and I'm the first vlogger to have done this (possibly the first in the world hehe). If nothing else, it's memorable. So, if you can brand yourself in a certain way that you think is cool and fun, do it! Pick a good name for your channel (if you haven't already), then get your .com, your Instagram, FB, make a website, stickers, etc. Brand yourself and get the word out. Every time you make a vlog, announce it everywhere. Some vloggers hold contests and such to get the word out, and others give-away or sell decals. Also, decal-trades with other vloggers is a great thing, because who doesn't love stickers? 
10. Be patient. Vlog because you love it, get involved and the subs and views will come in-time. Partner up (monetize) if you want. If not, don't. You probably won't get rich doing this but it just might pay for your gas along the way. 
