The social media explosion has meant the creation of many online tools and services enabling us to share our ideas with the rest of the web, the question then remains of which ones to use. This is very much down to individual preference and what you intend to get out of them but I feel there are some guidelines that should be followed regardless of your needs or experience.
Choose complimentary tools, not conflicting ones.
There are numerous services out there that perform the same essential functions so, rather than using a selection, choose one and stick to it. Sign up to a range of services so that you can evaluate their functionality and ease of use enabling you to make an informed choice about those you want to employ in your daily routine. Signing up a number of accounts in different places does give you somewhere to fall back on should the unthinkable happen.
Do not have content on multiple sites or it will become unmanageable. Sticking to one service also increases your profile on that service which in turn may lead to more exposure or followers. Select one video hosting service and one audio service to be your main repositories.
The key to effectively using the tools is to not spread yourself too thinly or else you will not be able to keep up with the conversation in any meaningful way. By all means have profiles on multiple sites so that you can be found but do most of your networking on just one. You will most likely find that a large proportion of your contacts will also be set up on sites across the board.
Time is also a big factor here, if you don't have any then things aren't going to work out too well. Keeping up your network up to date requires a considerable time investment if you are to really achieve want you want with it - don't enter in to this lightly.