For newbies in trading I would suggest to just try with a small amount first and learn how this market works.
Every market is different so every market has its own learning curve. If you want to be invested then research projects and hold your shares
mid to longterm and do not daytrade. There are enough proofs that most daytraders lose money in the long run in every market. The biggest winners have always been
the ones who invested longterm. Just think about bitcoin. Recently I read a post from a guy in 2011. He wrote that he is sad because he sold all of his 1700btc at 0,30$
and now its 8$. Enough said

We all know that around summer time this year most altcoins went up extremely fast and big in price, right?
So isn't it normal that a big sell off taking place at some point? Especially in such a new market people getting scared and dump their holdings when the market goes
down a little bit and then it goes down more and more - chain reaction. It's very bad for people who bought alts at the top. So you have two options, hodling or selling with a loss. I would always prefer the first option.
Be patient and hodl. A lot of alts will come back someday and some probably never come back so I hope you diversified your portfolio.

Out of these you mentioned my favorites are Decred, Waves, Lisk, IOTA, SONM, EOS.
Hard to say which one will settle the race. Diversification is a good thing sometimes

I would only do midterm to longterm investments with that money. I think a good way is to look for a good project with a good an active team behind it which still seems to be undervalued.
Most people loose money trading short term that's a fact.

I only invested in one ico so far and that is ong.social. Who knows if that was the best choice but I just liked the work they already did and how active they are in the community. I will hold the coins longterm. Normally I do not invest in icos because like mentioned from others many times, most of the time price drops hard at the beginning so often there is a good chance to
buy cheap. Another advantage of not investing in ico is that you are not putting your money at risk before there is even a tradable coin released on an exchange.

I really like "spectiv". Looks like the have a solid team and I think that virtual reality will be one of the fastest growing markets
in near future.

Of course nobody can predict the exact time. But if you are not able to monitor the market all day and catch the right moment
I think the best way is to add step by step to some of your favorite altcoins when pullbacks happen but also always keep some btc. This way when altcoins
start growing big again you are already invested. Much better than jumping on the train when it has already left the station in my opinion.

If it's about investing 500$ I think it's not the best way to put it in Ethereum or other already big coins.
Of course there is still a lot of room to grow also for the big ones but maybe if you can just invest that small amount I would
choose a coin which is still cheap and more under the radar (probably undervalued) with a good project that has an ongoing developement with a good team behind it. Something like SONM, ENIGMA, NLC, 1ST etc. etc.
There are a lot of good projects out there. For example you can choose a business sector you are interested in and put that money into a project you like most out of that sector.

I hold some because I think the idea of the project is really good and there is definitely a use case. I am patient. But since I can not find any information about the progress of the project
I am a little bit confused. Guess I am not the only one 

Of course you can not be 100% sure if something is a scam or not. But there are many good sources all over the internet where you can inform yourself
about a project as much as possible. I am not a big fan of crypto youtubers but there are some really good guys who take very deep looks into many ico's.
You can watch some of the videos to get some insights and then do your own research and decide for yourself which ico maybe worth investing. I think that is a good way especially for people
who are new to the crypto space. But please do not follow them blindly. Always do your own research.