General advice? Become detached from your property and don't leave anything of any value to you there.
Pros/cons/pitfalls? You may not make any money from it !
Furnished or unfurnished - pros/cons and what if any difference to the price? Furnished - there are Fire Safety Standards for all upholstery, beds etc, more things to suffer wear and tear and debate damage over. Depends on your intended tenant and if long or short term . Makes very little price difference.
How to set rental price? Ask agent and look in local papers
Agency - good/bad experiences. What to look for, what to avoid? Communication was poor with ours and they didn't accurately account the rental income and tax deductions until IR picked it up.
Agency Fee - How much, and what could I expect them to do? 10% to market proeprty, vet prospective tenants, do viewings, draw up agreement, collect rent. 15% for management service, as before plus day to day issues such as if something goes wrong. Extra costs such as Professional Inventory services.
Agency - anyone got a good one to recommend or know of ones that are best avoided? Look for one which is NAEA and ARLA affiliated and which seems to have a high local profile and good reputation.
How to decide who to rent to? How to evaluate applicants - how to find a good tenant? Use agency to run the checks and references. Decide in advance what market you are aiming at - families, company lets, sharers (different rules may apply ) DSS or not. Also any ground rules like no pets, non smokers which can be used early on to eliminate those unsuitable.
Best rent payment methods? Depends if via agent or not (they'll deduct their fees plus VAT, any costs, and pass balance on to your bank a/c
What if I have a delinquent tenant? ?
Do company lets exist anymore? Yes ime but they are more fussy (require professional cleaning and higher spec stuff) and you cannot control who actually lives there.
Lease terms/tips? Usually it is an Assured Tenancy for 6 or 12 months with a fixed notice period or renewal thereafter. Specify which utilities, water and Council tax they are responsible for and which you (like Ground Rent and maintenance charges). An agent has a standard agreement on which yours would be based.
Can I specify no pets or non smoker? Yes
Security deposit info - how much? At least a month's rent with a month rent paid in advance
What happens if there is damage to flat/fixture/fittings/furniture? Insurance policies - you maintain your own buildings and lower contents policies plus take a separate lettings policy which will cover some , but not all , eventualities including non-payment of rent.
How to ascertain general wear and tear vs true damage? Subjective , you need a very thorough inventory and photos. As if you had lived there, so general scuffs and repainting would be wear and tear. Generally you expect it back in the condition you handed it over (plus some wear and tear) but you could pay for a professional clean beforehand so they have to do so at the end.
Anything else I haven't thought of? Tax situation - rental income is taxable in UK but you can offset maintenance , cost of agent, mortgage interest etc against it. Gas Safety Certificate and an electrical inspection(consider a service contract)legally required. If your property is leasehold you may need to write to the Freeholder for permission plus your Mortgage and Insurance companies.
hth