Online resources to follow

Youtube
Extra Credits (https://www.youtube.com/user/ExtraCreditz). This discusses various different aspects of game design/mechanics in short episodes, providing insights for how to avoid pitfalls and make your game features great.

Three minute game design (https://www.youtube.com/watch?v=vw76jqF1nkI). This introduces game design concepts from the ground up in 3 minute episodes.

Reddit
Follow /r/gamedesign (game design questions and articles are posted here), /r/gamedev (similar, but for development aspects), /r/unity2d (for unity-specific questions, tutorials, etc.)

Other
TIGSource -http://forums.tigsource.com/

Good forum for finding tutorials and posting your work. Notable developers such as Notch (Minecraft) and Phil Fish (Fez) started out on here.

/agdg/ -http://boards.4chan.org/vg/catalog#s=agdg(searches the catalog for the current thread)

If you can ignore the idiots and anime posters there are some great developers that post there that will answer questions/help with your issues (such as the developer of Risk of Rain).

If you don't want to go there they have a wiki with useful information -http://agdg.me/wiki/index.php/Welcome_to_the_AGDG_Wikiand a website showcasing games made mainly by people from there http://justlikemakegame.net/