Bike won’t start after oil change

Changed the oil in my 2003 Suzuki VS 800 on Monday. Bike lights and warning signals come on but it won’t turn over.

The bike was sitting for a year before I bought it. Always turned over well. Tried cold start.

Should I have changed the oil filter as well? And use a battery tender inside since my garage is unheated?

Also I did the oil when it was on the kickstand. Heard some people say it should be level and not tilted. So should I drain some excess oil till it’s at the exact level? I’m planning on that. I’ve heard of foaming from excess oil.

Also spark plugs? Just to be safe, get new ones?